Fix path to wordlists

Index: discovery/dnssearch.py
--- discovery/dnssearch.py.orig
+++ discovery/dnssearch.py
@@ -63,7 +63,7 @@ class dns_force():
     def __init__(self, domain, dnsserver, verbose=False):
         self.domain = domain
         self.nameserver = dnsserver
-        self.file = "wordlists/dns-big.txt"
+        self.file = "${PREFIX}/share/theharvester/wordlists/dns-big.txt"
         #self.file = "wordlists/dns-names.txt"
         self.subdo = False
         self.verbose = verbose