Pass /dev/null as stdin when calling ceph commands

[b-ranto]

Currently, we run these commands with default stdin which resolves to
tty from which the daemon is run. For commands like 'rbd watch '
which wait for an input, this can result in commands being hung forever.

The patch fixes this by attaching the stdin to /dev/null so the commands
like that will get EOF on stdin and exit immediately.

Signed-off-by: Boris Ranto branto@redhat.com

[b-ranto]

This PR also contains patch for an issue where we can hang forever for certain commands that do expect some input from stdin since these two commits would conflict otherwise.

[jcsp]

Curious about what would ever use this, as the rados tool is all about access to the contents of pools rather than administration?

[b-ranto]

@jcsp we had a downstream request for this

https://bugzilla.redhat.com/show_bug.cgi?id=1347137

[jcsp]

Please see my comments on the BZ.

[andrewschoen]

@b-ranto The BZ mentions this is a fix for 2.1, did you meant to target the 1.4 branch of calamari then?

[b-ranto]

@andrewschoen I test most of my fixes on 1.3 (it is easier for me that way at the moment) and then I "backport" them to 1.4.

@jcsp I have re-worked this so that we provide the global stats and pool stats in a more standard way:

#492

-> I'll update this PR to only contain the fix for

https://bugzilla.redhat.com/show_bug.cgi?id=1354459

EDIT: Done, this is already targeted for bz1354459 only, see #492 for the other issue.