Fail if monit reload failed; don't mask the error.

This is necessary for the scenario when you push a new, broken monit
config out, and then set a state=reloaded handler - the error was
previously swallowed so you could end up with successful play but missing
monitoring (!).

Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Merge pull request #7334 from lamby/devel

Fail if monit reload failed; don't mask the error.