Add translation support to plugin modules

Changed modules:
* sahara/plugins/base.py
* sahara/plugins/general/exceptions.py
* sahara/plugins/general/utils.py
* sahara/plugins/hdp/ambariplugin.py
* sahara/plugins/hdp/clusterspec.py
* sahara/plugins/hdp/configprovider.py
* sahara/plugins/hdp/hadoopserver.py
* sahara/plugins/hdp/versions/version_1_3_2/services.py
* sahara/plugins/hdp/versions/version_1_3_2/versionhandler.py
* sahara/plugins/hdp/versions/version_2_0_6/services.py
* sahara/plugins/hdp/versions/version_2_0_6/versionhandler.py
* sahara/plugins/provisioning.py
* sahara/plugins/spark/config_helper.py
* sahara/plugins/spark/plugin.py
* sahara/plugins/spark/scaling.py
* sahara/plugins/vanilla/hadoop2/config.py
* sahara/plugins/vanilla/hadoop2/config_helper.py
* sahara/plugins/vanilla/hadoop2/run_scripts.py
* sahara/plugins/vanilla/hadoop2/scaling.py
* sahara/plugins/vanilla/hadoop2/validation.py
* sahara/plugins/vanilla/plugin.py
* sahara/plugins/vanilla/v1_2_1/config_helper.py
* sahara/plugins/vanilla/v1_2_1/scaling.py
* sahara/plugins/vanilla/v1_2_1/versionhandler.py

Change-Id: Ia3dacd7ce5a77e8b51747d9c8e1a17fab266395e
Merge "Add translation support to plugin modules"