lib/oe/patch: exclude "From <hash>" from commit message when PATCHTOOL is "git"

If you leave "From <hash>" lines in the commit message it can actually
break git rebase because it tries to interpret the line in the context
of the current repository, and if the hash is invalid then a rebase
will blow up with:

  fatal: git cat-file: could not get object info

or in newer git versions:

  error: unable to find <hash>
  fatal: git cat-file <hash>: bad file

(I hit this when I tried to do a devtool upgrade on openssl to 1.0.2i
the first time I did "git rebase --skip")

(From OE-Core rev: 19a6b18ac23cb2d7bb89203f774b2bee7f0cb03c)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oe/patch.py

@@ -317,6 +317,7 @@ class GitApplyTree(PatchTree):
     def interpretPatchHeader(headerlines):
         import re
         author_re = re.compile('[\S ]+ <\S+@\S+\.\S+>')
+        from_commit_re = re.compile('^From [a-z0-9]{40} .*')
         outlines = []
         author = None
         date = None
@@ -346,6 +347,9 @@ class GitApplyTree(PatchTree):
                 # git is fussy about author formatting i.e. it must be Name <email@domain>
                 if author_re.match(authorval):
                     author = authorval
+            elif from_commit_re.match(line):
+                # We don't want the From <commit> line - if it's present it will break rebasing
+                continue
             outlines.append(line)
         return outlines, author, date, subject