Update SM to latest trunk

Pulls in CP-6697 to let us bind mount FileSRs to /var/run/sr-mount

This is useful for Ubuntu which clears /var/run on boot
xcp-sm: update file list

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #475 from djs55/sm-path-fix

@BobBall's #473 with a build fix