Travis: Remove unused LINUX env variable

.travis.yml

@@ -47,22 +47,22 @@ matrix:
   include:
     - os: linux
       compiler: gcc
-      env: LINUX=1 TRAVIS_NO_EXPORT=YES ENABLE_COVERALLS=ON  ASAN=OFF
+      env: TRAVIS_NO_EXPORT=YES ENABLE_COVERALLS=ON  ASAN=OFF
     - os: linux
       compiler: gcc
-      env: LINUX=1 TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF ASAN=ON
+      env: TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF ASAN=ON
     - os: linux
       compiler: gcc
-      env: LINUX=1 SHARED_BUILD=ON TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF  ASAN=OFF
+      env: SHARED_BUILD=ON TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF  ASAN=OFF
     - os: linux
       compiler: gcc
-      env: LINUX=1 SHARED_BUILD=ON TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF  ASAN=OFF
+      env: SHARED_BUILD=ON TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF  ASAN=OFF
     - os: linux
       compiler: clang
-      env: LINUX=1 TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF ASAN=ON
+      env: TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF ASAN=ON
     - os: linux
       compiler: clang
-      env: LINUX=1 SHARED_BUILD=ON TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF  ASAN=OFF
+      env: SHARED_BUILD=ON TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF  ASAN=OFF
 
 install:
   - if [ $ANDROID ]; then wget -c http://dl.google.com/android/ndk/android-ndk-${PV}-${PLATF}.tar.bz2 && tar xf android-ndk-${PV}-${PLATF}.tar.bz2 ; fi