Fix a crash with OnClientLogin()
Fix a crash with OnClientLogin()

A client doesn't necessarily have a network after logging in (e.g. could have
used an invalid network name).

This is another crash found by exoa, thanks.

Signed-off-by: Uli Schlachter <346c0ad49ac8427b61b3b55abbe37dc0ebd524f2@znc.in>

wolfy1339/znc,KiNgMaR/znc,kashike/znc,dgw/znc,BtbN/znc,withinsoft/znc,badloop/znc,Adam-/znc,aarondunlap/znc,elyscape/znc,elyscape/znc,Hasimir/znc,jantman/znc,TuffLuck/znc,wolfy1339/znc,evilnet/znc,Adam-/znc,ollie27/znc,psychon/znc,TingPing/znc,Kriechi/nobnc,Kriechi/znc,Mikaela/znc,Hasimir/znc,trisk/znc,jreese/znc,Kriechi/znc,wolfy1339/znc,TuffLuck/znc,TuffLuck/znc,znc/znc,ollie27/znc,jpnurmi/znc,Adam-/znc,KiNgMaR/znc,znc/znc,Hasimir/znc,znc/znc,Kriechi/znc,jantman/znc,kashike/znc,Mkaysi/znc,ollie27/znc,YourBNC/znc,Mikaela/znc,TuffLuck/znc,psychon/znc,jpnurmi/znc,markusj/znc,Kriechi/nobnc,wolfy1339/znc,anthonyryan1/znc,Kriechi/znc,jpnurmi/znc,DarthGandalf/znc,jreese/znc,TingPing/znc,Kriechi/nobnc,GLolol/znc,jantman/znc,Phansa/znc,TingPing/znc,reedloden/znc,jpnurmi/znc,Mkaysi/znc,Zarthus/znc,evilnet/znc,Mikaela/znc,trisk/znc,evilnet/znc,Mikaela/znc,ollie27/znc,jreese/znc,Phansa/znc,jantman/znc,jreese/znc,YourBNC/znc,badloop/znc,elyscape/znc,YourBNC/znc,badloop/znc,ollie27/znc,YourBNC/znc,BtbN/znc,trisk/znc,wolfy1339/znc,TuffLuck/znc,TingPing/znc,KielBNC/znc,withinsoft/znc,GLolol/znc,Mkaysi/znc,anthonyryan1/znc,Hasimir/znc,kashike/znc,jantman/znc,elyscape/znc,TingPing/znc,BtbN/znc,evilnet/znc,withinsoft/znc,jantman/znc,TuffLuck/znc,withinsoft/znc,Kriechi/znc,KielBNC/znc,jreese/znc,Zarthus/znc,markusj/znc,Kriechi/znc,GLolol/znc,ollie27/znc,badloop/znc,TingPing/znc,psychon/znc,anthonyryan1/znc,markusj/znc,Zarthus/znc,withinsoft/znc,BtbN/znc,aarondunlap/znc,KielBNC/znc,anthonyryan1/znc,znc/znc,wolfy1339/znc,DarthGandalf/znc,evilnet/znc,Zarthus/znc,TuffLuck/znc,Mkaysi/znc,znc/znc,psychon/znc,badloop/znc,Zarthus/znc,KielBNC/znc,Adam-/znc,BtbN/znc,markusj/znc,KiNgMaR/znc,KielBNC/znc,Hasimir/znc,YourBNC/znc,Mikaela/znc,aarondunlap/znc,reedloden/znc,reedloden/znc,dgw/znc,Phansa/znc,GLolol/znc,Hasimir/znc,trisk/znc,znc/znc,GLolol/znc,Phansa/znc,KiNgMaR/znc,evilnet/znc,aarondunlap/znc,trisk/znc,Mikaela/znc,dgw/znc,aarondunlap/znc,DarthGandalf/znc,markusj/znc,Mkaysi/znc,DarthGandalf/znc,jpnurmi/znc,Mkaysi/znc,kashike/znc,GLolol/znc,Phansa/znc,aarondunlap/znc,reedloden/znc,kashike/znc,anthonyryan1/znc,Adam-/znc,KiNgMaR/znc,jpnurmi/znc,Hasimir/znc,reedloden/znc,badloop/znc,KiNgMaR/znc,kashike/znc,Phansa/znc,jpnurmi/znc,Adam-/znc,jreese/znc,withinsoft/znc,DarthGandalf/znc,anthonyryan1/znc,Adam-/znc,Mkaysi/znc,psychon/znc,markusj/znc,dgw/znc,YourBNC/znc,KielBNC/znc,badloop/znc,elyscape/znc,dgw/znc,aarondunlap/znc,BtbN/znc,anthonyryan1/znc,elyscape/znc,DarthGandalf/znc,trisk/znc,reedloden/znc,Zarthus/znc,dgw/znc,psychon/znc,Mikaela/znc