Revert "Trimmed the branch to only the gazebo_msgs sub directory"

This reverts commit c6e47ce0106c97f01d7ed48eb23fd0635f70f7c3.
Rebase from 'upstream' (no changes)
Trimmed the branch to only the gazebo_msgs sub directory
Revert "Trimmed the branch to only the gazebo_msgs sub directory"

This reverts commit 4fa45a8fa2d12269dc93bcec1f659d95b03cfb3a.
Rebase from 'upstream'
Trimmed the branch to only the gazebo_msgs sub directory