Fix spurious task library test failure

Change-Id: I6e78d7a2d8959c711f7889e142408ba64e7be41c
Fix test error when testing createrepo output

From createrepo 0.9.9 (RHEL 6.4 onwards), generating
database output is the default. This patch tries to
ensure that database output is not generated.

Change-Id: I5eb6fb887a7d0ec523bf8fb076c3ee0a800a7ebb