cgiserv: removed buggy redundant PID file management code:

 Removing this code fixes #215 and allows to run cgiserv as "nobody".

 When cgiserv started directly PID management is unnecessary;

 When cgiserv started by service manager PID management is in the way of
 starting as different user.

Please note that stop/restart "features" are to be removed as per #218.

Please review.

Signed-off-by: Dmitry Smirnov <onlyjob@member.fsf.org>