init script: Consider warnings as non-fatal when starting

Naemon can start just fine even with warnings, so don't let the
init script bail out. Without this patch, people would otherwise
see that naemon doesn't start, but the logfile says everything's
ok and that there are some warnings.

This is a rework of a patch from Franky Van Liederkerke, submitted
as pull request #61. The reworks were suggested by Sven Nierlein.

Original-patch-by: Franky Van Liederkerke
Signed-off-by: Andreas Ericsson <ae@op5.se>