Optional pattern 32bit moved from desktops to optional_default_patterns

- Pattern 32bit does not exist on some architectures but it used to be
  reported as missing then. Making it optional changes the installer
  to just logging that the pattern is missing.
- bnc#876760
Changes and version
Merge pull request #37 from kobliha/optional_default_patterns

Optional pattern 32bit moved from desktops to optional_default_patterns