minor #1315 Fix env variable in travis.yaml (danez)

This PR was merged into the 1.3 branch.

Discussion
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Fix env variable in travis.yaml

SYMFONY_DEPS_VERSION=3 was never evaluated correctly as the before_scripts are comparing with 3.0
The tests were still installing 3.0, as minimumStability=dev, but maybe it is nice fixing that.

Commits
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7c3c8d72 Fix env variable in travis.yaml

.travis.yml

@@ -29,6 +29,6 @@ matrix:
         - php: 5.6
           env: SYMFONY_DEPS_VERSION=2.8
         - php: 5.6
-          env: SYMFONY_DEPS_VERSION=3
+          env: SYMFONY_DEPS_VERSION=3.0
         - php: 7.0
         - php: hhvm