record: teach parsepatch() about non-git style headers

These changes are not useful to record itself, since it is hard coded
to always generate git style diffs.  But it makes parsepatch() more
generally useful for parsing normal patch files.

hgext/record.py

@@ -42,7 +42,7 b' def scanpatch(fp):'
         line = lr.readline()
         if not line:
             break
-        if line.startswith('diff --git a/'):
+        if line.startswith('diff --git a/') or line.startswith('diff -r '):
             def notheader(line):
                 s = line.split(None, 1)
                 return not s or s[0] not in ('---', 'diff')
@@ -70,7 +70,8 b' class header(object):'
 
     XXX shoudn't we move this to mercurial/patch.py ?
     """
-    diff_re = re.compile('diff --git a/(.*) b/(.*)$')
+    diffgit_re = re.compile('diff --git a/(.*) b/(.*)$')
+    diff_re = re.compile('diff -r .* (.*)$')
     allhunks_re = re.compile('(?:index|new file|deleted file) ')
     pretty_re = re.compile('(?:new file|deleted file) ')
     special_re = re.compile('(?:index|new|deleted|copy|rename) ')
@@ -110,10 +111,14 b' class header(object):'
                 return True
 
     def files(self):
-        fromfile, tofile = self.diff_re.match(self.header[0]).groups()
-        if fromfile == tofile:
-            return [fromfile]
-        return [fromfile, tofile]
+        match = self.diffgit_re.match(self.header[0])
+        if match:
+            fromfile, tofile = match.groups()
+            if fromfile == tofile:
+                return [fromfile]
+            return [fromfile, tofile]
+        else:
+            return self.diff_re.match(self.header[0]).groups()
 
     def filename(self):
         return self.files()[-1]