Redmine #6161: Core support for HA checking

As HA is enterprise only feature in core there are some stubs added
that will allow agent to check HA status.
Redmine #6161: Removing HA related log message so in core.

Right now core users wont be flooded by enterprise related message.
Merge pull request #1807 from pasinskim/ha

Redmine #6161: Core support for HA checking
cf-upgrade should not close STDOUT of all forked commands

Now both STDOUT and STDERR of forked commands go to STDOUT and STDERR of
cf-upgrade. Previously it was just closed and e.g. dpkg was failing
because of that.

Modify the test scripts to actually test that.
Use even more compatible sed regular expression for AIX.
Merge pull request #1821 from jimis/cfupgrade

cf-upgrade should not close STDOUT of all forked commands