Bump Impala version to 2.7.0
Bump Impala version to 2.7.0

Change-Id: Ibf67f61936260e66a5bb0d7fe63e4930850252c6
Reviewed-on: http://gerrit.cloudera.org:8080/3167
Reviewed-by: Bharath Vissapragada <f23dbca75acdac4082d6a05c290fc03565dada86@cloudera.com>
Tested-by: Internal Jenkins

cloudera/Impala,michaelhkw/incubator-impala,cloudera/Impala,cloudera/Impala,michaelhkw/incubator-impala,cloudera/Impala,cloudera/Impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,cloudera/Impala,cloudera/Impala