bitbake: bitbake: fetch2/git: add nobranch option for SRC_URI to skip SHA validating for branch

For rebased git tree, some commits doesn't exist in any branch, and such commits are
valid in tag, the change is useful for such case.

(Bitbake rev: f594cb9f5a18dd0ab2342f96ffc6dba697b35f65)

Signed-off-by: Zhenhua Luo <zhenhua.luo@freescale.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/fetch2/git.py

@@ -101,6 +101,8 @@ class Git(FetchMethod):
 
         ud.rebaseable = ud.parm.get("rebaseable","0") == "1"
 
+        ud.nobranch = ud.parm.get("nobranch","0") == "1"
+
         # bareclone implies nocheckout
         ud.bareclone = ud.parm.get("bareclone","0") == "1"
         if ud.bareclone:
@@ -289,8 +291,13 @@ class Git(FetchMethod):
         return True
 
     def _contains_ref(self, ud, d, name):
-        cmd =  "%s branch --contains %s --list %s 2> /dev/null | wc -l" % (
-            ud.basecmd, ud.revisions[name], ud.branches[name])
+        cmd = ""
+        if ud.nobranch:
+            cmd = "%s log --pretty=oneline -n 1 %s -- 2> /dev/null | wc -l" % (
+                ud.basecmd, ud.revisions[name])
+        else:
+            cmd =  "%s branch --contains %s --list %s 2> /dev/null | wc -l" % (
+                ud.basecmd, ud.revisions[name], ud.branches[name])
         try:
             output = runfetchcmd(cmd, d, quiet=True)
         except bb.fetch2.FetchError: