Remove env overrides from travis

It's replacing CC from autotools with the one from env. Everything
seems to work fine without it.

.travis-script.sh

@@ -3,7 +3,7 @@ set -ev
 
 ./autogen.sh
 ./configure
-make
+make --jobs=2
 
 if [ -n "$VALGRIND_TEST" ]; then
   libtool execute valgrind --leak-check=full --error-exitcode=1 -- \

.travis.yml

@@ -5,7 +5,6 @@ env:
   - KVZ_DISABLE_AVX2=1
   - TEST_DIM=264x130
   - TEST_FRAMES=10
-  - MAKEFLAGS="--jobs=2 --environment-overrides"
 
 sudo: false