block_motd: Update internal state when server has no MOTD
block_motd: Update internal state when server has no MOTD

Otherwise if we request MOTD and the server doesn't have one the module
would have incorrect state.

markusj/znc,GLolol/znc,kashike/znc,kashike/znc,DarthGandalf/znc,BtbN/znc,BtbN/znc,markusj/znc,dgw/znc,BtbN/znc,dgw/znc,DarthGandalf/znc,Zarthus/znc,GLolol/znc,BtbN/znc,jreese/znc,dgw/znc,elyscape/znc,dgw/znc,markusj/znc,BtbN/znc,dgw/znc,kashike/znc,GLolol/znc,jreese/znc,jreese/znc,psychon/znc,jreese/znc,kashike/znc,kashike/znc,markusj/znc,znc/znc,psychon/znc,GLolol/znc,markusj/znc,Zarthus/znc,znc/znc,DarthGandalf/znc,kashike/znc,jreese/znc,markusj/znc,jreese/znc,Zarthus/znc,DarthGandalf/znc,DarthGandalf/znc,elyscape/znc,Zarthus/znc,znc/znc,elyscape/znc,Zarthus/znc,elyscape/znc,GLolol/znc,psychon/znc,znc/znc,DarthGandalf/znc,BtbN/znc,elyscape/znc,Zarthus/znc,GLolol/znc,dgw/znc,znc/znc,psychon/znc,elyscape/znc,psychon/znc,znc/znc,psychon/znc