Use known working translate-toolkit snapshot for testing

This way we can avoid surprises when translate-toolkit git breaks and
our tests will fail. Once they release version supporting Python 3, we
should switch to it.
Signed-off-by: Michal Čihař <michal@cihar.com>

.travis.yml

@@ -46,15 +46,15 @@ notifications:
 matrix:
   include:
     - python: "3.3"
-      env: CI_PIP_DEPS="Django>=1.9,<1.10 https://github.com/translate/translate/zipball/master"
+      env: CI_PIP_DEPS="Django>=1.9,<1.10 https://github.com/translate/translate/zipball/de3f080abf6f2fecfca97d283a58eb6824d8078e"
     - python: "3.4"
-      env: CI_PIP_DEPS="Django>=1.9,<1.10 https://github.com/translate/translate/zipball/master"
+      env: CI_PIP_DEPS="Django>=1.9,<1.10 https://github.com/translate/translate/zipball/de3f080abf6f2fecfca97d283a58eb6824d8078e"
     - python: "3.5"
-      env: CI_PIP_DEPS="Django>=1.9,<1.10 https://github.com/translate/translate/zipball/master"
+      env: CI_PIP_DEPS="Django>=1.9,<1.10 https://github.com/translate/translate/zipball/de3f080abf6f2fecfca97d283a58eb6824d8078e"
     - python: "3.5"
-      env: CI_PIP_DEPS="Django>=1.9,<1.10 https://github.com/translate/translate/zipball/master" CI_MODE=lint
+      env: CI_PIP_DEPS="Django>=1.9,<1.10 https://github.com/translate/translate/zipball/de3f080abf6f2fecfca97d283a58eb6824d8078e" CI_MODE=lint
     - python: "3.5"
-      env: CI_PIP_DEPS="Django>=1.9,<1.10 https://github.com/translate/translate/zipball/master" CI_MODE=selenium
+      env: CI_PIP_DEPS="Django>=1.9,<1.10 https://github.com/translate/translate/zipball/de3f080abf6f2fecfca97d283a58eb6824d8078e" CI_MODE=selenium
 addons:
   apt:
     packages: