parser: fix parsing of patches with headings

parser: fix parsing of patches with headings

Some people tend to use lines full of '=' as a fancy way to format headings
in their commit messages in a rst-like style. However, the current parser
treats such lines as a beginning of a diff.

The only currently used tool that produces diffs with '=' lines is quilt in
the default configuration. However, even with quilt, the diff looks this
way:

    Index: dir/file
    ===================================================================
    --- dir.orig/file
    +++ dir/file
    @@ ...etc...

It's enough to match on the "Index:" line. The state of the state machine is
kept at 1 when it encounters the '=' line, thus it's safe to remove the
match on '=' completely.

[This prevents us from properly parsing metadata out of the changelog. -dcz ]

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Reviewed-by: Stephen Finucane <stephen@that.guru>
(cherry picked from commit 67faf96ab96d93252c89967ef766bcbe8214c0fc)