Add the missing semicolon (#841)

diff --git a/.travis.yml b/.travis.yml
index 08ff498..3107791 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -72,7 +72,7 @@
   fi
 - if [ ! -z "$TRAVIS_TAG" ] ; then
       export GIT_TAG=$TRAVIS_TAG;
-      export TAG=true
+      export TAG=true;
   fi
 - echo "The GIT_TAG of this Travis build is $GIT_TAG."