Bug 1270801 - Remove additional package hashes

Since the PyPI API response has since stabilised, so we no longer need
to list hashes for both .zip and .tar.gz:
https://bitbucket.org/pypa/pypi/issues/436/peep-hash-failures-due-to-being-served-zip

requirements/common.txt

@@ -56,18 +56,13 @@ https://github.com/jeads/datasource/archive/v0.10.0.tar.gz#egg=datasource==0.10.
     --hash=sha256:7b62a9517c25750d03809076053758d5740de45a8c6c6d9194c2c0885b4a3ea2
 
 # Required by jsonschema
-# Similar to PyYAML below, the hash for the .zip has also been listed due to:
-# https://bitbucket.org/pypa/pypi/issues/436/peep-hash-failures-due-to-being-served-zip
-functools32==3.2.3-2 --hash=sha256:f6253dfbe0538ad2e387bd8fdfd9293c925d63553f5813c4e587745416501e6d \
-    --hash=sha256:89d824aa6c358c421a234d7f9ee0bd75933a67c29588ce50aaa3acdf4d403fa0
+functools32==3.2.3-2 --hash=sha256:89d824aa6c358c421a234d7f9ee0bd75933a67c29588ce50aaa3acdf4d403fa0
 
 # Required by django-rest-swagger
 Unipath==1.1 --hash=sha256:e6257e508d8abbfb6ddd8ec357e33589f1f48b1599127f23b017124d90b0fff7
 
-# Required by django-rest-swagger (PyYAML is distributed in two forms:
-# .zip and .tar.gz, and pip likes to switch between them:
-# https://bugzilla.mozilla.org/show_bug.cgi?id=1266426)
-PyYAML==3.11 --hash=sha256:c36c938a872e5ff494938b33b14aaa156cb439ec67548fcab3535bb78b0846e8 --hash=sha256:19bb3ac350ef878dda84a62d37c7d5c17a137386dde9c2ce7249c7a21d7f6ac9
+# Required by django-rest-swagger
+PyYAML==3.11 --hash=sha256:19bb3ac350ef878dda84a62d37c7d5c17a137386dde9c2ce7249c7a21d7f6ac9
 
 # Used directly plus required by django-browserid, WebTest & responses
 requests==2.9.1 --hash=sha256:113fbba5531a9e34945b7d36b33a084e8ba5d0664b703c81a7c572d91919a5b8