Fix dead-lock on exit
Fix dead-lock on exit

Change the mutex to recursive to avoid possible dead-lock on signal
handling (^C).

lcheylus/haka,Wingless-Archangel/haka,lcheylus/haka,Wingless-Archangel/haka,haka-security/haka,haka-security/haka,haka-security/haka,nabilbendafi/haka,nabilbendafi/haka,lcheylus/haka,LubyRuffy/haka,nabilbendafi/haka,LubyRuffy/haka