setup.py: don't use pyasn1 to 0.3.3 until pyasn1-modules is updated to support it

Latest pyasn1-modules hard codes pyasn1-0.3.2, so this currently break our tests.
Ref: https://github.com/etingof/pyasn1-modules/issues/4

setup.py

@@ -36,7 +36,7 @@ setup(name='fdroidserver',
           'paramiko',
           'Pillow',
           'apache-libcloud >= 0.14.1',
-          'pyasn1',
+          'pyasn1 <= 0.3.2',
           'pyasn1-modules',
           'python-vagrant',
           'PyYAML',