Disable ppc64le test environment on Travis CI

as this semi-official beta option has suddenly reverted to a standard x86_64 environment causing spurious failures

.travis.yml

@@ -25,14 +25,14 @@ matrix:
         - TARGET_BOX=LINUX64
         - BTYPE="BINARY=64"
 
-    - <<: *test-ubuntu
-      os: linux-ppc64le
-      before_script:
-        - COMMON_FLAGS="DYNAMIC_ARCH=1 TARGET=POWER8 NUM_THREADS=32"
-      env:
-        # for matrix annotation only
-        - TARGET_BOX=PPC64LE_LINUX
-        - BTYPE="BINARY=64 USE_OPENMP=1"
+        #    - <<: *test-ubuntu
+        #      os: linux-ppc64le
+        #      before_script:
+        #        - COMMON_FLAGS="DYNAMIC_ARCH=1 TARGET=POWER8 NUM_THREADS=32"
+        #      env:
+        #        # for matrix annotation only
+        #        - TARGET_BOX=PPC64LE_LINUX
+        #        - BTYPE="BINARY=64 USE_OPENMP=1"
 
     - <<: *test-ubuntu
       env: