[PATCH 0/1][SRU][Trusty/Utopic/Vivid/Wily](upstream) xfs: give all workqueues rescuer threads

[Dave Chiluk]

Patch applies cleanly in Wily/Vivid
Patch needs a mild "backport" for Trusty/Utopic

This fixes a possible deadlock situation in XFS when under memory pressure with high XFS thread utilization.

User tested hotfix against lts-wily kernel only.  Problem is not easily reproducible so testing against other kernels has not been performed.

Dave Chiluk.