download mesa 10.3.1 from ftp

scripts/travis_before_install.sh

@@ -29,8 +29,13 @@ if [[ ${TRAVIS_OS_NAME} == "linux" ]]; then
 
     mapbox_time "build_mesa" \
     git clone git://anongit.freedesktop.org/git/mesa/mesa && \
-    git checkout mesa-10.3.1 && \
-    cd mesa && \
+    git tag -l && \
+    cd ../ && \
+    wget ftp://ftp.freedesktop.org/pub/mesa/10.3.1/MesaLib-10.3.1.tar.gz && \
+    wget ftp://ftp.freedesktop.org/pub/mesa/10.3.1/MesaLib-10.3.1.tar.gz.sig && \
+    gpg --verify MesaLib-10.3.1.tar.gz.sig && \
+    tar xzvf MesaLib-10.3.1.tar.gz && \
+    cd Mesa-10.3.1 && \
     ./autogen.sh --with-gallium-drivers=svga,swrast --disable-dri \
         --enable-xlib-glx --enable-glx-tls --with-llvm-prefix=/usr/lib/llvm-3.4 \
         --without-va && \