MissionBicycle error: no cache file on O_TRUNC
free pdata in in_cache
avoid thread unsafeness
forgot short cut on O_TRUNC
added parenthesis for clarity
mostly added commentary
warn if we have a cache file on O_CREAT
Merge pull request #14 from pantheon-systems/nullfilenameerror

MissionBicycle error: no cache file on O_TRUNC