calculate child time from very beginning of fork, omit rounding to avoid issues
calculate child time from very beginning of fork, omit rounding to avoid issues

git-svn-id: 70c0b718c09296cad0cf258c7c3baebeee6f4020@12 2aabfe31-cc40-457c-aec7-21ad9ce7fb7d

billfloat/spawn,curious/spawn,tra/spawnling,rfc2822/spawn