Remove redundant variable definition

The same Volume variable is defined with two names in the same scope.
Merge the names and remove one of the definitions.

Change-Id: I021697b42791bc6323c5fa0d9704d27ecfe2c8c1
(cherry picked from commit d98fabe2aa8df0e421a69130c1d787705209682d)
Merge "Remove redundant variable definition" into cm-11.0