sanitycheck: filter: add support to use env variables

Added support in the sanitycheck to use env variable
value in the filter.

Change-Id: I76388dc04557dcd31e651d23ae8edf96a8fe2474
Jira: ZEP-592
Signed-off-by: Javier B Perez <javier.b.perez.hernandez@intel.com>
1 file changed