Increase requrement to GitPython 0.3.2

The 0.3.1 has bug in handling branches which prevents project to be
imported.

Fixes #374

docs/install.rst

@@ -12,7 +12,7 @@ Django (>= 1.4)
     https://www.djangoproject.com/
 Translate-toolkit (>= 1.9.0, 1.10.0 or newer strong recommended)
     http://toolkit.translatehouse.org/
-GitPython (>= 0.3)
+GitPython (>= 0.3.2)
     https://github.com/gitpython-developers/GitPython
 Git (>= 1.0)
     http://git-scm.com/

trans/requirements.py

@@ -130,7 +130,7 @@ def get_versions():
         name,
         url,
         mod.__version__,
-        '0.3',
+        '0.3.2',
     ))
 
     name = 'Git'