Rename hash_questions.c, for consistency.

bld/Android.mk

@@ -11,7 +11,7 @@ LOCAL_SRC_FILES :=  bpf.c cache.c dbus.c dhcp.c dnsmasq.c \
 		    radv.c slaac.c auth.c ipset.c domain.c \
 	            dnssec.c dnssec-openssl.c blockdata.c tables.c \
 		    loop.c inotify.c poll.c rrfilter.c edns0.c arp.c \
-		    crypto.c dump.c ubus.c metrics.c hash_questions.c \
+		    crypto.c dump.c ubus.c metrics.c hash-questions.c \
                     domain-match.c
 
 LOCAL_MODULE := dnsmasq