The need to mess with binfmt_misc super-blocks only exists
in OpenVZ kernel and troubes all the other users. So make
this code get compiled-out by default.

In VZ-builds the BINFMT_MISC_VIRTUALIZED should be put into
.config file before running make.

https://github.com/xemul/criu/issues/235
travis-ci: success for Don't compile in binfmt_misc dumping code by default (rev3)
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Reviewed-by: Dmirty Safonov <dsafonov@virtuozzo.com>