.travis.yml: Update unsupported Python version

coala supports Python 3.4.2 and later as from commit
58b9f41 but the commit missed updating the travis.yml
file. This fixes the issue with the CI failure on
unsupported job by changing the unsupported version
from 3.4.3 to 3.4.1.

Closes coala#6017

.travis.yml

@@ -50,7 +50,7 @@ jobs:
       <<: *disable_global
       stage: unsupported
       script: .misc/check_unsupported.sh
-    - python: 3.4.3
+    - python: 3.4.1
       <<: *disable_global
       stage: unsupported
       script: .misc/check_unsupported.sh