bump up maven compiler plugin version

Author: beiwei30

pom.xml

@@ -130,7 +130,7 @@
         <profile.name>oss</profile.name>
 
         <!-- for maven compiler plugin -->
-        <maven_compiler_plugin_version>2.3.2</maven_compiler_plugin_version>
+        <maven_compiler_plugin_version>3.5.1</maven_compiler_plugin_version>
         <java_source_version>1.6</java_source_version>
         <java_target_version>1.6</java_target_version>
         <file_encoding>UTF-8</file_encoding>