LU-424 tests: conf-sanity test 55, 56, 58 failure fixes

LU-424 tests: conf-sanity test 55, 56, 58 failure fixes

The MGS service was not started in conf-sanity test 55,
56 and 58 with separate MGS and MDT configuration. This
patch fix the issue.

Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: I0c01955b4baf81535959cdbf38bf84e7acb04ddf
Reviewed-on: http://review.whamcloud.com/1870
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-by: Yu Jian <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>