[cmake] Link against major.minor.patch version of libmysqlclient to avoid runtime conflict

Summary: Someone shipped a libmysqlclient.so.21 in the system but that was of older version that didn't have mysql_result_metadata (actually it did - but locally and not exported). As a result libmysql_test_api is failing to locate mysql_result_metadata at runtime. The fix is to always link against major.minor.patch version that we are building to avoid conflicts.

Reviewed By: zhichengzhu

Differential Revision: D17507965

Author: yizhang82

libmysql/CMakeLists.txt

@@ -332,7 +332,7 @@ IF(UNIX)
   # Name of shared library is libmysqlclient on Unix
   SET(UNIX_OUTPUT_NAME OUTPUT_NAME mysqlclient)
   SET(UNIX_VERSION     VERSION     "${OS_SHARED_LIB_VERSION}")
-  SET(UNIX_SOVERSION   SOVERSION   "${SHARED_LIB_MAJOR_VERSION}")
+  SET(UNIX_SOVERSION   SOVERSION   "${OS_SHARED_LIB_VERSION}")
 ENDIF()
 
 # Merge several convenience libraries into one big mysqlclient