run git submodule sync due to some random errors in Travis

Author: skvark

setup.py

@@ -27,15 +27,16 @@ def main():
 
         import pip.vcs.git
         g = pip.vcs.git.Git()
+        g.run_command(["submodule", "sync"])
         use_depth = g.get_git_version() >= type(g.get_git_version())("1.8.4")
 
         g.run_command(["submodule", "update", "--init", "--recursive"] +
-                      (["--depth=1"] if use_depth else []) +
+                      ["--depth=1"] if use_depth else [] +
                       [cmake_source_dir])
 
         if build_contrib:
             g.run_command(["submodule", "update", "--init", "--recursive"] +
-                          (["--depth=1"] if use_depth else []) +
+                          ["--depth=1"] if use_depth else [] +
                           ["opencv_contrib"])
 
         del use_depth, g, pip