Bug#974981: gem2deb: ruby:Depends should mangle the version for alpha, beta and rc versions

[Pirate Praveen]

Package: gem2deb
Severity: wishlist

With ruby-azure-storage-common, the dependency generated by gem2deb 
causes

unsat-dependency: ruby-faraday-middleware:amd64 (>= 1.0.0.rc1)

Even when experimental has ruby-faraday-middleware (and experimental is 
enabled).

This should be changed to 1.0.0~rc1. Probably the same regexp used in 
watch file uversionmangle could be reused.