Ignore non-installed conflicting packages
Ignore non-installed conflicting packages

When removing conflicting packages, if the packages to be removed aren't
already installed (which they might not be, e.g.: syslog-ng doesn't seem
to be present on a clean install of SLES 12 SP1), zypper will exit with
return code 104, which causes mkcrowbar to bail out.

felixsch/mkcrowbar