Skip MigrateConfigToGit if gclient config is non trivial.

gclient.py

Index: gclient.py
diff --git a/gclient.py b/gclient.py
index 3007487a5930d0f09aeac1260defe3be12bd4360..1cb36d72eb568e90f5a11763bd75d1dff56f392c 100755
--- a/gclient.py
+++ b/gclient.py
@@ -1265,12 +1265,16 @@ want to set 'managed': False in .gclient.
     # dump an updated .gclient file that preserves the ordering of the original.
     a = ast.parse(self.config_content, options.config_filename, 'exec')
     modified = False
-    solutions = [elem for elem in a.body if 'solutions' in
-                 [target.id for target in elem.targets]]
+
+    solutions = [elem for elem in a.body if elem.__class__ is ast.Assign and
+                 'solutions' in [target.id for target in elem.targets]]
     if not solutions:
       return self
     solutions = solutions[-1]
     for solution in solutions.value.elts:
+      # Non-trivial assignment to solutions.
+      if solution.__class__ is not ast.Dict:
+        continue
       # Check for obsolete URL's
       url_idx = ast_dict_index(solution, 'url')
       if url_idx == -1: