debian: revert duplicated 'release2' branch setting in whonix.conf
debian: improve cleaning up before dpkg-source

Remove all the binary packages from source tree, so they will not land
in debian source package.
debian: generate package with properly set target distribution

This requires adding distribution release in version string, so the same
package built for different dist version will have different versions.
Otherwise name collision occurs at least in reprepro (apt repository
maintaining tool).
debian: create repo metadata always in the same chroot environment

reprepro is sensitive to database library (libdb) version, so always
needs to be called in the same env. Regardless of packages being
imported.
debian: ensure the last commit is also included in changelog message
Add CHECK_BRANCH option to validate current branch before building

Set CHECK_BRANCH=1 in builder.conf to ensure that the current branch is
the same as the configured one. Especially useful when using the same
qubes-src dir (symlink) in multiple qubes-builder environments.
Merge branch 'master' of git://git.qubes-os.org/marmarek/qubes-builder
nrgaway: Added signing key and cleanup up whonix.conf a bit
Merge branch 'master' into wheezy
nrgaway: added signing key and added back in private repos