modify .travis.yml only for NVIDIA_GPU build

Author: wgy0804

.travis.yml

@@ -7,12 +7,12 @@ os:
 env:
   - JOB="-p NVIDIA-GPU -o Centos"
   - JOB="-p NVIDIA-GPU -o Ubuntu"
-  - JOB="-p AMD_GPU -o Centos"
-  - JOB="-p AMD_GPU -o Ubuntu"
-  - JOB="-p X86-ONLY -o Centos"
-  - JOB="-p X86-ONLY -o Ubuntu"
-  - JOB="-p ARM -o Centos"
-  - JOB="-p ARM -o Ubuntu"
+  #- JOB="-p AMD_GPU -o Centos"
+  #- JOB="-p AMD_GPU -o Ubuntu"
+  #- JOB="-p X86-ONLY -o Centos"
+  #- JOB="-p X86-ONLY -o Ubuntu"
+  #- JOB="-p ARM -o Centos"
+  #- JOB="-p ARM -o Ubuntu"
 
 compiler:
   - gcc