oo-diagnostics: Read /proc instead of using ps

In test_mcollective_context, read /proc/#{pid}/attr/current to determine
the process's domain instead of using using the output of ps, which is
affected by mcstransd.

This commit fixes bug 1119923.
Merge pull request #5606 from Miciah/bug-1119923-oo-diagnostics-read-slashh-proc-instead-of-using-ps

Merged by openshift-bot