Merge remote-tracking branch 'origin/bare_callsign' into easypost-patches

Closes #7

…ire protocol by git command (SSH transport)

Summary:
Makes `ssh-connect` compatible with Git v2 wire protocol over SSH

More details about git V2 wire: https://opensource.googleblog.com/2018/05/introducing-git-protocol-version-2.html

`git` command (2.18+) passes extra options (`-o "SendEnv GIT_PROTOCOL"`) to underlying `ssh` command to enable v2 wire protocol (environment variable enabling new protocol).

Phabricator `ssh-connect` command doesn't understand `-o` options and interprets it as host parts hence when you enable git v2 all clones/ls-remotes crash with:
```
#0 ExecFuture::resolvex() called at [<phabricator>/src/applications/repository/storage/PhabricatorRepository.php:525]
#1 PhabricatorRepository::execxRemoteCommand(string, PhutilOpaqueEnvelope) called at [<phabricator>/src/applications/repository/engine/PhabricatorRepositoryPullEngine.php:400]
#2 PhabricatorRepositoryPullEngine::loadGitRemoteRefs(PhabricatorRepository) called at [<phabricator>/src/applications/repository/engine/PhabricatorRepositoryPullEngine.php:343]
#3 PhabricatorRepositoryPullEngine::executeGitUpdate() called at [<phabricator>/src/applications/repository/engine/PhabricatorRepositoryPullEngine.php:126]
#4 PhabricatorRepositoryPullEngine::pullRepositoryWithLock() called at [<phabricator>/src/applications/repository/engine/PhabricatorRepositoryPullEngine.php:40]
#5 PhabricatorRepositoryPullEngine::pullRepository() called at [<phabricator>/src/applications/repository/management/PhabricatorRepositoryManagementUpdateWorkflow.php:59]
#6 PhabricatorRepositoryManagementUpdateWorkflow::execute(PhutilArgumentParser) called at [<phutil>/src/parser/argument/PhutilArgumentParser.php:441]
#7 PhutilArgumentParser::parseWorkflowsFull(array) called at [<phutil>/src/parser/argument/PhutilArgumentParser.php:333]
#8 PhutilArgumentParser::parseWorkflows(array) called at [<phabricator>/scripts/repository/manage_repositories.php:22]
COMMAND
git ls-remote '********'
STDOUT
(empty)
STDERR
ssh: Could not resolve hostname -o: Name or service not known
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.
at [<phutil>/src/future/exec/ExecFuture.php:369]
```

Test Plan:
How to reproduce:
1. add repository to Phabricator which is accessed via `ssh`
2. Use git 2.18+
3. Enable wire protocol in `/etc/gitconfig`:
```
[protocol]
    version = 2
```
4. Try refreshing repository: `phabricator/bin/repository update somecallsing`
5. Repository update fails with `ssh: Could not resolve hostname -o: Name or service not known`

after this changes - updates will succeed

Reviewers: epriestley, Pawka, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D19542