Unicode fixes for RPM generation

Includes debian generation fixes for 32305ba99a0eddb106c75b97dcd2c559af0769bb and f213ec199c7a47e5ed1ce4ce695d723a65fd13d2 and fixes https://github.com/ros-infrastructure/bloom/issues/196 for RPMs as well.

I know we've talked about it before, but we should merge the common code between debian and RPM generation, or at the very least start putting functions like this in a common file.

In any case, this will fix it for now.