@m3elloa and @Mark93 this may have been down to a little hickup in the updates where if one updated within a small time window directly after updates were available Rockstor failed to configure the new 4.6 kernel as the default, but still knew it should be default; hence the message.
See the following post from @suman for an explanation:
From the posting times it would look like @m3elloa may also have been caught by this as @aehinson was in that thread.
And as @Mark93 's most eloquent (and helpful) post requests “Let us know if it works”.
ie in your case of presumably updating within this small problematic time window, a simple
yum update
may sort things (Hopefully).