Verify the read config. in ConfigWriter only when offline
Verify the read config. in ConfigWriter only when offline

Otherwise logs get full of critical errors when the configuration is
being sent from WConfd to ConfigWriter in the middle of a job that
modifies the configuration (just as in the case of _WriteConfig).

This should be fully solved once WConfd itself does all the verification
checks (issue #759).

Signed-off-by: Petr Pudlak <9d19625f8ee825a2c398462ed335cbcf98f79c32@google.com>
Reviewed-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>

andir/ganeti,yiannist/ganeti,ganeti/ganeti,apyrgio/ganeti,mbakke/ganeti,mbakke/ganeti,grnet/snf-ganeti,ganeti/ganeti,leshchevds/ganeti,ganeti/ganeti,leshchevds/ganeti,yiannist/ganeti,leshchevds/ganeti,mbakke/ganeti,ganeti-github-testing/ganeti-test-1,bitemyapp/ganeti,grnet/snf-ganeti,dimara/ganeti,andir/ganeti,bitemyapp/ganeti,onponomarev/ganeti,yiannist/ganeti,onponomarev/ganeti,apyrgio/ganeti,ganeti-github-testing/ganeti-test-1,andir/ganeti,dimara/ganeti