Revert "track added/removed/modified patch automatically"

This reverts commit b6ccac1ebd9cac5998118a7bb119508ade6b47fe.

This kind of functionality does not belong into vc. Source services
have far more knowledge about changes applied to packages and thus are
far more suitable to generate proper changelog entries. For example:

 - tar_scm can generate changes entries from git logs
 - refresh_patches can generate changes entries for added, removed
   and rebased patches (it does that semi-automatically)

For both services, changelog generation is _opt-int_. That means it has
to be enabled explicitly via the 'changesgenerate' parameter.

Lastly, the format was broken anyway...