Support local FROM/FULLNAME lookups through posix_getpwnam() against /etc/passwd.
Support local FROM/FULLNAME lookups through posix_getpwnam() against
/etc/passwd.

This is useful for small site operations where IMAP accounts equal local
accounts and no LDAP or other datasource is available.

Freeaqingme/Z-Push-contrib,RavenB/Z-Push-contrib,mta59066/Z-Push-contrib,fmbiete/Z-Push-contrib