scripts/combo-layer: avoid error when config file is outside repo

Avoid displaying the error from the "git status" command we use to check
the status of the config file if the config file is outside of the
repository (a situation that is already handled).

(From OE-Core rev: 9d3e54057673348e85ba479705c4ffaad56973d6)

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

scripts/combo-layer

@@ -79,7 +79,7 @@ class Configuration(object):
             logger.error("ERROR: patchutils package is missing, please install it (e.g. # apt-get install patchutils)")
             sys.exit(1)
 
-def runcmd(cmd,destdir=None):
+def runcmd(cmd,destdir=None,printerr=True):
     """
         execute command, raise CalledProcessError if fail
         return output if succeed
@@ -90,7 +90,8 @@ def runcmd(cmd,destdir=None):
         subprocess.check_call(cmd, stdout=out, stderr=out, cwd=destdir, shell=True)
     except subprocess.CalledProcessError,e:
         out.seek(0)
-        logger.error("%s" % out.read())
+        if printerr:
+            logger.error("%s" % out.read())
         raise e
 
     out.seek(0)
@@ -233,7 +234,7 @@ def action_update(conf, args):
     # Step 7: commit the updated config file if it's being tracked
     relpath = os.path.relpath(conf.conffile)
     try:
-        output = runcmd("git status --porcelain %s" % relpath)
+        output = runcmd("git status --porcelain %s" % relpath, printerr=False)
     except:
         # Outside the repository
         output = None