commands: Don't lie when logging

Lying logs are not a lot better than none at all. This patch makes
Naemon log unknown service commands as unknown service commands, instead
of unknown host commands.

Signed-off-by: Anton Lofgren <anton.lofgren@gmail.com>
commands: Add missing SEND_CUSTOM_SVC_NOTIFICATION

This patch adds in the implementation of SEND_CUSTOM_SVC_NOTIFICATION
which was accidentally removed in a previous overhaul of the command
code.

This fixes issue #65.

Reported-by: Johan Ryberg <johan@securit.se>
Signed-off-by: Anton Lofgren <anton.lofgren@gmail.com>
Merge pull request #67 from catharsis/issue-65

Issue 65