Fixed segfault checking command line arguments
Fixed segfault checking command line arguments

With inputs like ./hydra -l admin -P passwords/dictionary.txt
hydra gives a segmentation fault. Now checks if index < argc after
trying to access to argv[index]

gortiz7487/hydragon,easy1z/thc-hydra,killbug2004/thc-hydra,3L3N4/thc-hydra,liorvh/thc-hydra,bgarrels/thc-hydra,f0r34chb3t4/thc-hydra,fr34k8/thc-hydra,macbook47/thc-hydra-custom,gortiz7487/hydragon,easy1z/thc-hydra,veggiespam/thc-hydra,jasonchaffee/thc-hydra,3L3N4/thc-hydra,vanhauser-thc/thc-hydra,darrencocco/thc-hydra,dalinhuang/thc-hydra,veggiespam/thc-hydra,fr34k8/thc-hydra,macbook47/thc-hydra-custom,shresthaaanish/thc-hydra,macbook47/thc-hydra-custom,darrencocco/thc-hydra,darrencocco/thc-hydra,bgarrels/thc-hydra,liorvh/thc-hydra,3L3N4/thc-hydra,jorik041/thc-hydra,f0r34chb3t4/thc-hydra,darrencocco/thc-hydra,jasonchaffee/thc-hydra,daviwesley/thc-hydra,easy1z/thc-hydra,bgarrels/thc-hydra,killbug2004/thc-hydra,veggiespam/thc-hydra,daviwesley/thc-hydra,shresthaaanish/thc-hydra,f0r34chb3t4/thc-hydra,jasonchaffee/thc-hydra,jorik041/thc-hydra,jorik041/thc-hydra,f0r34chb3t4/thc-hydra,jasonchaffee/thc-hydra,bgarrels/thc-hydra,gortiz7487/hydragon,vanhauser-thc/thc-hydra,shresthaaanish/thc-hydra,dalinhuang/thc-hydra,3L3N4/thc-hydra,killbug2004/thc-hydra,gortiz7487/hydragon,dalinhuang/thc-hydra,daviwesley/thc-hydra,veggiespam/thc-hydra,daviwesley/thc-hydra,macbook47/thc-hydra-custom,jorik041/thc-hydra,shresthaaanish/thc-hydra,dalinhuang/thc-hydra,liorvh/thc-hydra,easy1z/thc-hydra,liorvh/thc-hydra