cmdutil: pass in parsed patch to tryimportone() (API)
Previously, we parsed the patch in tryimportone(). This assumes the
input is in a patch format that needs to be parsed. We want to support
feeding in data from other formats. So let's let the caller handle the
parsing.
One wonky thing about patch parsing is that patch.extract() creates
a temp file to hold the diffs and it is up to tryimportone() to
unlink that temp file. I'll improve this in a subsequent commit.
Differential Revision: https://phab.mercurial-scm.org/D3305
(binary:application/octet-stream)