Merge branch '2fa-message-improvement' into 'master'

Improved 2FA warning message about lost codes

Fixes internal issue: https://dev.gitlab.org/gitlab/gitlabhq/issues/2472

The warning message now clearly states that access will be lost of the 2FA recovery codes are not saved.

/cc @sytses @JobV

See merge request !1175

app/views/profiles/two_factor_auths/_codes.html.haml

 %p.slead
   Should you ever lose your phone, each of these recovery codes can be used one
-  time each to regain access to your account. Please save them in a safe place.
+  time each to regain access to your account. Please save them in a safe place, or you
+  %b will
+  lose access to your account.
 
 .codes.well
   %ul