The flag --security-opt doesn't use the colon separator (:) anymore
to divide keys and values, instead it uses the equal symbol (=) for
consistency with other similar flags, like --storage-opt.

Deprecated in release: v1.11.0
Target for removal in release: v17.06

https://docs.docker.com/engine/deprecated/

 #653
Signed-off-by: Radostin Stoyanov <rstoyanov1@gmail.com>