Freeze server dependencies to the same version used for 1.5.3

.travis.yml

@@ -1,6 +1,8 @@
 language: python
 python:
+- '3.4'
 - '3.5'
+- '3.6'
 sudo: false
 cache: pip
 install:

requirements.txt

@@ -1,7 +1,7 @@
 jsonschema>=2.4.0
-aiohttp>=1.3.5,<=1.4.0 # pyup: ignore
-aiohttp-cors==0.5.1 # pyup: ignore
-yarl>=0.9.8,<0.10 # pyup: ignore
+aiohttp==1.2.0 # pyup: ignore
+aiohttp-cors==0.4.0 # pyup: ignore
+yarl==0.8.1 # pyup: ignore
 typing>=3.5.3.0 # Otherwise yarl fail with python 3.4 
 Jinja2>=2.7.3
 raven>=5.23.0