ensure master-dist retains Travis dist file commit history

* this is the corresponding change for Patternfly core

Author: priley86

scripts/publish.sh

@@ -25,6 +25,16 @@ git add dist --force
 git commit -m "Added files generated by Travis build"
 
 # Push to dist branch
-git push upstream $TRAVIS_BRANCH:$TRAVIS_BRANCH-dist --force -v
+EXISTING=`git ls-remote --heads https://github.com/"$TRAVIS_REPO_SLUG".git "$TRAVIS_BRANCH"-dist`
+
+if [ -n "$EXISTING" ]
+then
+  git fetch upstream $TRAVIS_BRANCH-dist:$TRAVIS_BRANCH-dist
+  git checkout $TRAVIS_BRANCH-dist
+  git merge -Xtheirs $TRAVIS_BRANCH --no-edit --ff
+  git push upstream $TRAVIS_BRANCH-dist --force -v
+else
+  git push upstream $TRAVIS_BRANCH:$TRAVIS_BRANCH-dist --force -v
+fi
 
 exit $?