various dumpcap related code cleanup: mainly #include's and capture engine related stuff svn path=/trunk/; revision=17327
no longer needs util.c, so it no longer includes routines that use host_ip_af(), so it no longer needs to define its own host_ip_af(). That also means dumpcap.c no longer needs to include <sys/socket.h>. svn path=/trunk/; revision=17278