Make accept-language tests work with webob 1.8.x

Masakari below test cases are failing due to webob 1.8.x:
..unit.api.openstack.test_wsgi.RequestTest.test_secondary
..unit.api.openstack.test_wsgi.RequestTest.test_asterisk
..unit.api.openstack.test_wsgi.RequestTest.test_from_request

Please see the logs:
http://logs.openstack.org/53/518653/1/check/openstack-tox-py27/76866e9/testr_results.html.gz

This patch is a copy of change:
I2034d30cc8d9354be80d39e05b8488cb99c32ecf which fixes similar
test cases in nova.

This patch also changes the `lower-constraints.txt` to make
the WebOb version same as other services.

Change-Id: Ic5234735267530f3b347126e1f0afa3e25f9e1fe

lower-constraints.txt

@@ -120,5 +120,5 @@ unittest2==1.1.0
 urllib3==1.22
 vine==1.1.4
 voluptuous==0.11.1
-WebOb==1.7.4
+WebOb==1.7.1
 wrapt==1.10.11

masakari/tests/unit/api/openstack/test_wsgi.py

@@ -71,7 +71,7 @@ class RequestTest(MicroversionedTest):
                       fakes.fake_get_available_languages)
 
         request = wsgi.Request.blank('/')
-        accepted = 'bogus;q=1.1, en-gb;q=0.7,en-us,en;q=.5,*;q=.7'
+        accepted = 'bogus;q=1, en-gb;q=0.7,en-us,en;q=0.5,*;q=0.7'
         request.headers = {'Accept-Language': accepted}
         self.assertEqual(request.best_match_language(), 'en_US')
 
@@ -82,7 +82,7 @@ class RequestTest(MicroversionedTest):
                       fakes.fake_get_available_languages)
 
         request = wsgi.Request.blank('/')
-        accepted = '*,es;q=.5'
+        accepted = '*,es;q=0.5'
         request.headers = {'Accept-Language': accepted}
         self.assertEqual(request.best_match_language(), 'en_GB')
 
@@ -100,7 +100,7 @@ class RequestTest(MicroversionedTest):
                       fakes.fake_get_available_languages)
 
         request = wsgi.Request.blank('/')
-        accepted = 'nn,en-gb;q=.5'
+        accepted = 'nn,en-gb;q=0.5'
         request.headers = {'Accept-Language': accepted}
         self.assertEqual(request.best_match_language(), 'en_GB')
 

requirements.txt

@@ -7,6 +7,7 @@ iso8601>=0.1.11 # MIT
 jsonschema<3.0.0,>=2.6.0 # MIT
 keystoneauth1>=3.4.0 # Apache-2.0
 keystonemiddleware>=4.17.0 # Apache-2.0
+WebOb>=1.7.1 # MIT
 microversion-parse>=0.2.1 # Apache-2.0
 oslo.config>=5.2.0 # Apache-2.0
 oslo.context>=2.19.2 # Apache-2.0