Fix travis config to allow pypy3.5-aiohttp failure instead of excluding

Author: lamenezes

.travis.yml

@@ -16,6 +16,8 @@ env:
 matrix:
   allow_failures:
     - env: TOX_SUFFIX="boto3"
+    - env: TOX_SUFFIX="aiohttp"
+      python: "pypy3.5-5.9.0"
   exclude:
     # Only run flakes on a single Python 2.x and a single 3.x
     - env: TOX_SUFFIX="flakes"
@@ -30,8 +32,6 @@ matrix:
       python: 2.7
     - env: TOX_SUFFIX="aiohttp"
       python: pypy
-    - env: TOX_SUFFIX="aiohttp"
-      python: "pypy3.5-5.9.0"
 python:
 - 2.7
 - 3.5