Medium: ldirectord: Get correct user for sending email (bnc#910497)

On sending email alert the "local part" of the sending mailaddress
(before @) is the "user" who start ldirectord.
This however does only work if you start /usr/sbin/ldirectord on a bash
shell.
Starting it via resource agent ocf:heartbeat:ldirectord seems not
forward the bash environment "$ENV{USER}".

/var/log/mail shows like this:
Dec 12 12:30:41 sles11sp301 postfix/qmgr[15049]: 06B94103B9D:
from=<@sles11sp301.vmhamming.suse.de>, size=608, nrcpt=1 (queue active)

The following change (using "getpwuid( $< )" instead) will fix that problem.