#26 pypi2deb target fails for versioned pypi packages

pypi2deb allows users to convert specific package versions to deb packages by specifying the package including a version number. For example instead of using "buildbot-www" one could use "buildbot-www_2.0.1" to convert version 2.0.1 to a deb package instead of the latest available version. Unfortunately the pypi2deb target fails for these kind of package names. The error is located in [pypi2deb.mk#L27](https://notabug.org/sumpfralle/makefilet/src/v0.5.3/include/pypi2deb.mk#L27). Packages without a specific version number would be followed by an underscore and the version of the package that is already covered by the `.*` expression. But versioned package names already contain the version and the underscore that is inserted by the `$*` expression. I see two solutions for this problem: 1. make the underscore optional (downside of false-positives where one pypi package name starts with the name of another package that is being built) 2. don’t fail the target just because the changes file can’t be found (which seems ok, given that `py2dsp` will fail if the package can’t be build by it)

fixed in ac3d075b8d02a4244c5f4721fda8eb4ca3e42fb8