zypp: Remap 'recommended' patches to 'BUGFIX'

openSUSE knows three patch categories:
* optional
* recommended
* security

PackageKit knows: LOW, ENHANCEMENT, NORMAL, BUGFIX, IMPORTANT, SECURITY

Remapping 'recommended' to 'BUGFIX' in PackageKits namespace
'optional' remains 'LOW' and security 'SECURITY'

https://bugzilla.opensuse.org/show_bug.cgi?id=733728