Fix IPMC checks for releasing.

* Finish the prototype of TLS of gRPC between agent and server.

* Fix for rat check.

* Update GRPCChannelManager.java

* Update AgentModuleGRPCProvider.java

* Upgrade netty version (#971)

* Make sure end user can't start gRPC server with and without SSL in the same port.

fixed maven 3.3.9 build issue caused by empty assembly ID on Ubuntu 16.04.2 using OpenJDK 1.8.0_151.

[INFO] Building apm-collector-boot 5.0.0-alpha
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ apm-collector-boot ---
[INFO] Deleting /home/steve/skywalking/incubator-skywalking/apm-collector/apm-collector-boot/target
[INFO] 
[INFO] --- maven-checkstyle-plugin:2.17:check (validate) @ apm-collector-boot ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.492 s
[INFO] Finished at: 2018-02-18T12:05:49-06:00
[INFO] Final Memory: 19M/235M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:2.17:check (validate) on project apm-collector-boot: Failed during checkstyle configuration: cannot initialize module Header - Unable to find: CHECKSTYLE_HEAD -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

2. Delete the history data before the setting that you can find the property name of history_delete_before_days in the application.yml file.

Make agent gRPC to be a collector module.
Make agent jetty to be a collector module.
Make agent stream to be a collector module.

Trace segment compute by http json stream test success.