travis: Fix travis failures

The ARM website changed, updated the URL for theh Linaro gcc to use '7'.

Their gcc 8 build seems to come from ARM, we can review how this works
later to get ARM gcc-8 in the container.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

Author: jgunthorpe

.travis.yml

@@ -48,7 +48,7 @@ service:
     - docker
 
 before_script:
-  - export LATEST_GCC_LINARO_URL=`wget -qO - https://releases.linaro.org/components/toolchain/binaries/latest/aarch64-linux-gnu/ | grep -o '<a href=['"'"'"].*gcc-linaro-.*x86_64_aarch64-linux-gnu.tar.xz['"'"'"]'  |  sed -e 's/^<a href=["'"'"']//' -e 's/["'"'"']$//'`
+  - export LATEST_GCC_LINARO_URL=`wget -qO - https://releases.linaro.org/components/toolchain/binaries/latest-7/aarch64-linux-gnu/ | grep -o '<a href=['"'"'"].*gcc-linaro-.*x86_64_aarch64-linux-gnu.tar.xz['"'"'"]'  |  sed -e 's/^<a href=["'"'"']//' -e 's/["'"'"']$//'`
   - export LATEST_GCC_LINARO_TAR=`basename $LATEST_GCC_LINARO_URL`
   - wget -q http://releases.linaro.org/$LATEST_GCC_LINARO_URL
   - mkdir $HOME/aarch64 && tar xf $LATEST_GCC_LINARO_TAR -C $HOME/aarch64 --strip 1