tidb-server: handle deprecated configuration item in config-check (#13142)

[sre-bot]

cherry-pick #13142 to release-3.0

---

What problem does this PR solve?

Make using tidb-ansible to rolling update TiDB smooth.

Providing that there is a "pessimistic.ttl = 40s" in the config file, before this PR:

➜  tidb git:(master) ✗ ./bin/tidb-server -config ./config/config.toml.example -config-check 
FATA[0000] config file ./config/config.toml.example contained unknown configuration options: pessimistic-txn.ttl

After this PR:

➜  tidb git:(relex-config-check) ✗ ./bin/tidb-server -config ./config/config.toml.example -config-check 
config check successful

➜  tidb git:(relex-config-check) ✗ ./bin/tidb-server -config ./config/config.toml.example -config-strict
[2019/11/07 21:34:48.432 +08:00] [WARN] [main.go:170] ["config file ./config/config.toml.example contained unknown configuration options: pessimistic-txn.ttl"]
[2019/11/07 21:34:48.432 +08:00] [INFO] [printer.go:40] ["Welcome to TiDB."] ["Release Version"=v4.0.0-alpha-730-g64ab90bda] ["Git Commit Hash"=64ab90bda3c88d25df30dbcbeca0c4d82dd86253] ["Git Branch"=relex-config-check] ["UTC Build Time"="2019-11-07 01:33:48"] [GoVersion="go version go1.13.1 linux/amd64"] ["Race Enabled"=false] ["Check Table Before Drop"=false] ["TiKV Min Version"=v3.0.0-60965b006877ca7234adaced7890d7b029ed1306]
[2019/11/07 21:34:48.433 +08:00] [INFO] [printer.go:53] ["loaded config"] [config="{\"host\":\"0.0.0.0\",\"advertise-address\":\"\",\"port\":4000,\"cors\":\"\",\"store\":\"mocktikv\",\"path\":\"/tmp/tidb\",\"socket\":\"\",\"lease\":\"45s\",\"run-ddl\":true,\"split-table\":true,\"token-limit\":1000,\"oom-use-tmp-storage\":true,\"oom-action\":\"log\",\"mem-quota-query\":34359738368,\"enable-streaming\":false,\"txn-local-latches\":{\"enabled\":false,\"capacity\":2048000},\"lower-case-table-names\":2,\"log\":{\"level\":\"info\",\"format\":\"text\",\"disable-timestamp\":null,\"enable-timestamp\":null,\"disable-error-stack\":null,\"enable-error-stack\":null,\"file\":{\"filename\":\"\",\"max-size\":300,\"max-days\":0,\"max-backups\":0},\"slow-query-file\":\"tidb-slow.log\",\"slow-threshold\":300,\"expensive-threshold\":10000,\"query-log-max-len\":4096,\"record-plan-in-slow-log\":1},\"security\":{\"skip-grant-table\":false,\"ssl-ca\":\"\",\"ssl-cert\":\"\",\"ssl-key\":\"\",\"cluster-ssl-ca\":\"\",\"cluster-ssl-cert\":\"\",\"cluster-ssl-key\":\"\"},\"status\":{\"status-host\":\"0.0.0.0\",\"metrics-addr\":\"\",\"status-port\":10080,\"metrics-interval\":15,\"report-status\":true,\"record-db-qps\":false},\"performance\":{\"max-procs\":0,\"max-memory\":0,\"stats-lease\":\"3s\",\"stmt-count-limit\":5000,\"feedback-probability\":0.05,\"query-feedback-limit\":1024,\"pseudo-estimate-ratio\":0.8,\"force-priority\":\"NO_PRIORITY\",\"bind-info-lease\":\"3s\",\"txn-total-size-limit\":104857600,\"tcp-keep-alive\":true,\"cross-join\":true,\"run-auto-analyze\":true},\"prepared-plan-cache\":{\"enabled\":false,\"capacity\":100,\"memory-guard-ratio\":0.1},\"opentracing\":{\"enable\":false,\"rpc-metrics\":false,\"sampler\":{\"type\":\"const\",\"param\":1,\"sampling-server-url\":\"\",\"max-operations\":0,\"sampling-refresh-interval\":0},\"reporter\":{\"queue-size\":0,\"buffer-flush-interval\":0,\"log-spans\":false,\"local-agent-host-port\":\"\"}},\"proxy-protocol\":{\"networks\":\"\",\"header-timeout\":5},\"tikv-client\":{\"grpc-connection-count\":4,\"grpc-keepalive-time\":10,\"grpc-keepalive-timeout\":3,\"commit-timeout\":\"41s\",\"max-batch-size\":128,\"overload-threshold\":200,\"max-batch-wait-time\":0,\"batch-wait-size\":8,\"enable-arrow\":true,\"region-cache-ttl\":600},\"binlog\":{\"enable\":false,\"ignore-error\":false,\"write-timeout\":\"15s\",\"binlog-socket\":\"\",\"strategy\":\"range\"},\"compatible-kill-query\":false,\"plugin\":{\"dir\":\"\",\"load\":\"\"},\"pessimistic-txn\":{\"enable\":true,\"max-retry-count\":256},\"check-mb4-value-in-utf8\":true,\"treat-old-version-utf8-as-utf8mb4\":true,\"enable-table-lock\":false,\"delay-clean-table-lock\":0,\"split-region-max-num\":1000,\"stmt-summary\":{\"max-stmt-count\":100,\"max-sql-length\":4096}}"]

What is changed and how it works?

Maintain a deprecated configure item list, if the unknown configure option belongs to the list,
return a warning instead of panic.

Check List

Tests

• Manual test (add detailed scripts or steps below)

Side effects

• Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch

[sre-bot]

/run-all-tests

[coocood]

LGTM

[jackysp]

LGTM

[sre-bot]

/run-all-tests