CLOUD-353 added image pre check to provision setup
CLOUD-357 added source image path as env. variable
Merge pull request #378 from sequenceiq/precheck-image

CLOUD-353 added image pre check to provision setup
Merge pull request #381 from sequenceiq/gcc-image

CLOUD-357 added image and tar name env. variables
CLOUD-341 update to Ambari 1.7.0
CLOUD-341 update ambari rest client to 1.7.18