Reduce Travis e-mail notifications on success (#790)
Reduce Travis e-mail notifications on success (#790)

Only send e-mail notifications from Travis when the build fails,
or transitions from failure to success.

Signed-off-by: Craig Rodrigues <c4b5a8c0fafd56ae12499ba1d5d55022dbe4108e@portworx.com>
pault84/openstorage,libopenstorage/openstorage,pault84/openstorage,pault84/openstorage,libopenstorage/openstorage,libopenstorage/openstorage