Make the error subsystem not crash if nerr_init hasn't been called.
Make the error subsystem not crash if nerr_init hasn't been
called.

TESTS=passed unittests
hongruiqi/clearsilver,alisonjoe/clearsilver,WillYee/clearsilver,alisonjoe/clearsilver,hobby/clearsilver,hljyunxi/clearsilver,hongruiqi/clearsilver,WillYee/clearsilver,hljyunxi/clearsilver,manuelluis/clearsilver,hljyunxi/clearsilver,manuelluis/clearsilver,hobby/clearsilver,hljyunxi/clearsilver,apfeltee/clearsilver,apfeltee/clearsilver,apfeltee/clearsilver,hobby/clearsilver,hljyunxi/clearsilver,apfeltee/clearsilver,WillYee/clearsilver,hljyunxi/clearsilver,alisonjoe/clearsilver,manuelluis/clearsilver,WillYee/clearsilver,hobby/clearsilver,hobby/clearsilver,hljyunxi/clearsilver,hczhang/clearsilver,hongruiqi/clearsilver,alisonjoe/clearsilver,hczhang/clearsilver,hongruiqi/clearsilver,hongruiqi/clearsilver,manuelluis/clearsilver,apfeltee/clearsilver,manuelluis/clearsilver,manuelluis/clearsilver,hljyunxi/clearsilver,manuelluis/clearsilver,alisonjoe/clearsilver,WillYee/clearsilver,hczhang/clearsilver,hongruiqi/clearsilver,hobby/clearsilver,apfeltee/clearsilver,hczhang/clearsilver,alisonjoe/clearsilver,manuelluis/clearsilver,alisonjoe/clearsilver,hczhang/clearsilver,hongruiqi/clearsilver,apfeltee/clearsilver,hobby/clearsilver,WillYee/clearsilver,hljyunxi/clearsilver,WillYee/clearsilver,WillYee/clearsilver,hobby/clearsilver,hczhang/clearsilver,alisonjoe/clearsilver,hobby/clearsilver,hczhang/clearsilver,apfeltee/clearsilver,hongruiqi/clearsilver,apfeltee/clearsilver,manuelluis/clearsilver,alisonjoe/clearsilver,hczhang/clearsilver,hczhang/clearsilver,WillYee/clearsilver,hongruiqi/clearsilver