Also fix path discovery for symlinks.

Use realpath instead of abspath so that ghar can find its directory even
if "ghar" is a symlink to the script, as well as the case where it's
invoked with a relative path. Also reformat line in accordance with
PEP8.

bin/ghar

@@ -312,7 +312,8 @@ def _init_repos():
 
 def main(args):
     # the ghar executable lives in <repo directory>/bin/ghar
-    args.ghar_dir = os.path.dirname(os.path.dirname(os.path.abspath(sys.argv[0])))
+    args.ghar_dir = os.path.dirname(os.path.dirname(
+        os.path.realpath(sys.argv[0])))
     _init_repos()
     if len(repos) <= 0:
         sys.stderr.write("No repos found in %s\n" % args.ghar_dir)