support android 4

[YangSen-qn]

1. 支持 api level 14
2. 处理偶现并发异常问题
3. 支持 okhttp 4.9

[codecov]

Codecov Report

Merging #463 (59bee19) into master (2e962b4) will decrease coverage by 0.75%.
The diff coverage is 74.34%.

@@             Coverage Diff              @@
##             master     #463      +/-   ##
============================================
- Coverage     71.04%   70.28%   -0.76%     
+ Complexity     1175     1163      -12     
============================================
  Files            92       93       +1     
  Lines          6054     6149      +95     
  Branches        913      920       +7     
============================================
+ Hits           4301     4322      +21     
- Misses         1135     1199      +64     
- Partials        618      628      +10     

Impacted Files	Coverage Δ
...src/main/java/com/qiniu/android/common/Config.java	86.36% <ø> (ø)
.../main/java/com/qiniu/android/common/Constants.java	0.00% <ø> (ø)
.../main/java/com/qiniu/android/common/ZonesInfo.java	78.57% <ø> (ø)
...main/java/com/qiniu/android/http/ResponseInfo.java	59.75% <ø> (ø)
.../java/com/qiniu/android/http/dns/DnsCacheInfo.java	55.00% <ø> (ø)
...droid/http/networkStatus/NetworkStatusManager.java	39.60% <ø> (ø)
.../http/networkStatus/UploadServerNetworkStatus.java	26.66% <ø> (ø)
.../qiniu/android/http/request/HttpSingleRequest.java	84.09% <ø> (ø)
...iniu/android/http/request/httpclient/ByteBody.java	100.00% <ø> (ø)
...roid/http/serverRegion/UploadServerFreezeUtil.java	64.70% <ø> (ø)
... and 39 more