[6.0] d40336ee4 Switch to clang 7 in our travis job

[Dridi Boukelmoune]

commit d40336ee4c8cf003fe23b48ae8c11eff5c71614d
Author: Federico G. Schwindt <fgsch at lodoss.net>
Date:   Wed Sep 26 09:10:54 2018 -0600

    Switch to clang 7 in our travis job

diff --git a/.travis.yml b/.travis.yml
index 1b0751c8f..da2bcbb8b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -13,14 +13,14 @@ matrix:
   - os: linux
     dist: trusty
     compiler: clang
-    env: CLANG=6.0 SAN_FLAGS="--enable-asan --enable-ubsan"
+    env: CLANG=7 SAN_FLAGS="--enable-asan --enable-ubsan"
     sudo: required
   - os: osx
     osx_image: xcode10
     compiler: clang
   allow_failures:
   - os: osx
-  - env: CLANG=6.0 SAN_FLAGS="--enable-asan --enable-ubsan"
+  - env: CLANG=7 SAN_FLAGS="--enable-asan --enable-ubsan"
 addons:
   apt:
     packages: