ci: Use llvm-5.0.1 to simplify target triple

Author: kulp

ci/before_install.sh

@@ -9,10 +9,7 @@ set -x
 set -o pipefail
 
 function llvm_linux_target_triple() {
-    case "$1" in
-        5.*)                echo "linux-x86_64-ubuntu14.04" ;;
-        *)                  echo "x86_64-linux-gnu-ubuntu-14.04" ;;
-    esac
+    echo "x86_64-linux-gnu-ubuntu-14.04"
 }
 
 function llvm_macos_target_triple() {
@@ -29,6 +26,7 @@ function llvm_version_triple() {
         3.6) echo "3.6.2" ;;
         3.7) echo "3.7.1" ;;
         3.8) echo "3.8.1" ;;
+        5.0) echo "5.0.1" ;;
         # By default, take the .0 patch release
         *)   echo "$1.0"  ;;
     esac