Fix change branch to master

pym/cl_builder.py

@@ -275,7 +275,7 @@ class cl_builder(color_print):
                         format(repname=gitName,
                                branch='master'))
                 changeBranch = self.runChroot(distrPath,
-                    "cd %s;git fetch;git checkout master"%gitDir)
+                    "cd %s;git fetch;git checkout master;git pull"%gitDir)
                 self.printByResult(changeBranch.success())
 
         self.applyTemplatesForSquash(distrPath)