chore(build): add an error message on failure to deploy documentation

.travis.yml

@@ -28,4 +28,4 @@ deploy:
   skip_cleanup: true
 
 after_success:
-  - test $TRAVIS_PULL_REQUEST == "false" && test $TRAVIS_BRANCH == "master" && bash ./.travis/deploy-docs.sh
+  - test $TRAVIS_PULL_REQUEST == "false" && test $TRAVIS_BRANCH == "master" && test $JOB == "build-docs" && bash ./.travis/deploy-docs.sh

.travis/deploy-docs.sh

@@ -18,11 +18,12 @@
 # Fail out on error
 set -eu -o pipefail
 
-DOCS_FOLDER="./doc/html"
+DOCS_FOLDER="./doc/html/"
 
 # Ensure docs exists
 if [ ! -d "$DOCS_FOLDER" ]
 then
+    echo "Docs deploy failing, no $DOCS_DIR present."
     exit 1
 fi