Fix an out-of-range access to std::string
Fix an out-of-range access to std::string

When we received a "PING" from a client without an argument, std::string would
throw a std::out_of_range exception which killed znc.

Thanks to Sm0ke0ut for reporting this.


git-svn-id: 3ad904ec35b89a071badd9cb0113dfe58093e920@2093 726aef4b-f618-498e-8847-2d620e286838

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