ci(Travis): Fix git commands in the doc publishing script
ci(Travis): Fix git commands in the doc publishing script

Make sure to pull the latest commits and tags, and don't do a `git clean` because it would remove docs for newly added services

watson-developer-cloud/ios-sdk,watson-developer-cloud/ios-sdk,watson-developer-cloud/ios-sdk,watson-developer-cloud/ios-sdk,watson-developer-cloud/ios-sdk