Recommended update for ruby-common

This update for ruby-common provides several fixes and enhancements:

- Help the solver to pick the right gem2rpm for the default Ruby version. (bsc#934328)
- Fix premature return from from gem install.
- Fail early if gem install fails, avoiding confusing error messages at the end of the build.
- Implement cleaner solution for the extensions doc dir.
- Do not overwrite options.otheropts.
- Fixed forwarding of options to gem install.
- Call ruby with -x from shell wrappers otherwise it might run into an endless loop.
- Add shell-launcher to avoid dependency on a fixed Ruby version.
- Ignore any files found in */.gem/*. In some versions of rubygems, gems that are installed
are also copied to ~/.gem/.

Fixed bugs
bnc#934328
[libsolv] zypper in ruby install ruby2.2 and 2.1
bnc#953771
[TRACKERBUG] Release of Portus build requirements to SLE-12 codestream
Selected Binaries
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