gluster: Corrected the skippedFile count setting

By mistake the skipped file count value was being assigned into
filesFailed field only and so was causing an issue.

Change-Id: Idc097b1dab5d948f67f2e08c7f590fddf89e55a2
Bug-Url: https://bugzilla.redhat.com/1020779
Signed-off-by: Shubhendu Tripathi <shtripat@redhat.com>