qtbase: Remove BLACKLIST files which are no longer active

Remove BLACKLIST files which are no longer valid because the mentioned
CI systems are no longer active:
 - opensuse-13.1
 - opensuse-42.1
 - rhel-7.1
 - rhel-7.2
 - rhel-7.3
 - ubuntu-14.04
or the testcases are no longer available:
 - QTBUG_14292_filesystem in qactiongroup

Change-Id: I80a4397059fafba169096440fdc07d45c76a1ed8
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>