checkCriuVersion: only ask criu once about its version
checkCriuVersion: only ask criu once about its version

If the version of criu has already been determined there is no need to
ask criu for the version again. Use the value from c.criuVersion.

v2:
 * reduce unnecessary code movement in the patch series
 * factor out the criu version parsing into a separate function

Signed-off-by: Adrian Reber <9f82b3db7475afbb412180fe9fab7c69d6ece340@redhat.com>

stefanberger/runc,laijs/runc,stefanberger/runc,adrianreber/runc,xiaochenshen/runc,crosbymichael/runc,mYmNeo/runc,xiaochenshen/runc,opencontainers/runc,wking/runc,docker/runc,crosbymichael/runc,hqhq/runc,cyphar/runc,justincormack/runc,xiaochenshen/runc,stefanberger/runc,mikebrow/runc,mikebrow/runc,mheon/runc,wking/runc,rhatdan/runc,rajasec/runc,rajasec/runc,kolyshkin/runc,opencontainers/runc,hqhq/runc,docker/runc,cyphar/runc,mYmNeo/runc,hqhq/runc,opencontainers/runc,wking/runc,laijs/runc,rhatdan/runc,justincormack/runc,kolyshkin/runc,opencontainers/runc,kolyshkin/runc,estesp/runc,justincormack/runc,estesp/runc,kolyshkin/runc,rhatdan/runc,mYmNeo/runc,cyphar/runc,mheon/runc,estesp/runc,crosbymichael/runc,sunyuan3/runc,adrianreber/runc,dqminh/runc,dqminh/runc,mheon/runc,adrianreber/runc,sunyuan3/runc,rajasec/runc,dqminh/runc,mikebrow/runc,dqminh/runc,sunyuan3/runc,laijs/runc,docker/runc,rhatdan/runc