packaging: Updated parsing of the tasks

This patch replaces the execRemoteSql call with
the parseRemoteSqlCall, which allows easier parsing
of the output during tasks and compensation check.

Then the lenght of the output is tested and actual
list of tasks is returned if necessary.

Change-Id: I3b1f24ef5e83cf09c01c3ebbb00375098ddc52c1
Bug-Url: https://bugzilla.redhat.com/921578
Bug-Url: https://bugzilla.redhat.com/912426
Signed-off-by: Alex Lourie <alourie@redhat.com>
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>