longevity tests: Set mounttable log level with vpath.
longevity tests: Set mounttable log level with vpath.

This log level might have a chance of capturing relevant messages.

Change-Id: I19b67791cf4e4e3c1170f863d9dc30a90fe18e15

vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref