Fix checkParser ordering.

Not much point throwing an exception if the server's state has
already been mucked up.

Change-Id: I3c64b46ab8c8f432a8276cb717b8816af1bea56a
Reviewed-on: http://gerrit.dmdirc.com/3640
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Greg Holmes <greg@dmdirc.com>