travis: Remove symbolic link

.travis.yml

@@ -13,16 +13,12 @@ addons:
       - g++-6
       - cmake
 script:  
-  # Link gcc-6 and g++-6 to their standard commands
-  - ln -s /usr/bin/gcc-6 /usr/local/bin/gcc
-  - ln -s /usr/bin/g++-6 /usr/local/bin/g++
-  
   # Export CC and CXX to tell cmake which compiler to use
   - export CC=/usr/bin/gcc-6
   - export CXX=/usr/bin/g++-6
 
   # Check versions of gcc, g++ and cmake
-  - gcc -v && g++ -v && cmake --version
+  - gcc-6 -v && g++-6 -v && cmake --version
 
   # Build
   - rm -rf build/