do not need to test lua53 on multiple archs

.travis.yml

@@ -249,33 +249,6 @@ matrix:
           - ninja-build
           - liblua5.2-dev
  
-    - os: linux
-      env:
-        - LUA_VERSION=lua53
-        - LLVM_VERSION=4.0.0
-        - LLVM_ARCHIVE_PATH=$HOME/clang+llvm.tar.xz
-        - COMPILER=clang++
-        - CPPFLAGS="-I $HOME/clang-$LLVM_VERSION/include/c++/v1"
-        - CXXFLAGS=-lc++
-        - PATH=$HOME/clang-$LLVM_VERSION/bin:$PATH
-        - LD_LIBRARY_PATH=$HOME/clang-$LLVM_VERSION/lib:$LD_LIBRARY_PATH
-      before_install:
-       - wget http://llvm.org/releases/$LLVM_VERSION/clang+llvm-$LLVM_VERSION-x86_64-linux-gnu-ubuntu-14.04.tar.xz -O $LLVM_ARCHIVE_PATH
-       - mkdir $HOME/clang-$LLVM_VERSION
-       - tar xf $LLVM_ARCHIVE_PATH -C $HOME/clang-$LLVM_VERSION --strip-components 1
-       - export PATH=$HOME/clang+llvm/bin:$PATH
-       - source ./install.deps.sh
-      compiler: clang
-      addons:
-        apt:
-          sources:
-          - ubuntu-toolchain-r-test
-          packages:
-          - gcc-4.9
-          - g++-4.9
-          - ninja-build
-          - liblua5.2-dev
-
     - os: osx
       osx_image: xcode7.3
       compiler: gcc