Remove PGPORT hack

It is no longer needed as pg9.5 is installed in its standard port.

.travis.yml

@@ -45,11 +45,8 @@ before_install:
     | sudo tee /etc/postgresql/9.5/main/pg_hba.conf
   - sudo /etc/init.d/postgresql restart 9.5
 
-  # save the postgres port for later usage
-  - sudo cat /etc/postgresql/9.5/main/postgresql.conf | grep ^port | grep -oh '[0-9]*' > .pg95.port
-
 install:
   - sudo make install
 
 script:
-  - PGPORT=$(cat .pg95.port) make test || { cat src/pg/test/regression.diffs; false; }
+  - make test || { cat src/pg/test/regression.diffs; false; }