merging PR Chaosthebot#501: fix Patchset from requests

Chaosthebot#501: fix Patchset from requests

Description:
Getting patch raise no error but was in fact empty.

:white_check_mark: PR passed with a vote of 7 for and 0 against, a weighted total of 7.0 and a threshold of 6.5, and a current meritocracy review.

Vote record:
@MUCHZER: 1
@PlasmaPower: 1
@Swizz: 1
@andrewda: 1
@e-beach: 1
@JustynC7: 1
@rhengles: 1

github_api/__init__.py

@@ -101,6 +101,6 @@ def __call__(self, method, path, **kwargs):
         try:
             data = resp.json()
         except:
-            data = None
+            data = resp.text
 
         return data

github_api/prs.py

@@ -330,11 +330,11 @@ def get_reactions_for_pr(api, urn, pr):
 
 def get_patch(api, urn, pr_num, raw=False):
     """ get the formatted or not patch file for a pr """
-    path = "/{urn}/pull/{pr}.patch".format(urn=urn, pr=pr_num)
+    path = "https://github.com/{urn}/pull/{pr}.patch".format(urn=urn, pr=pr_num)
     data = api("get", path)
     if raw:
         return data
-    return PatchSet(data)
+    return PatchSet.from_string(data)
 
 
 def post_accepted_status(api, urn, pr, voting_window, votes, total, threshold,