Stricter signatures to match the new bionic/libc/netbsd/resolv ones.

Change-Id: I690858b85303addc030540bce8512ec9a1e18b4a
diff --git a/ResolverController.h b/ResolverController.h
index a21e077..2eec417 100644
--- a/ResolverController.h
+++ b/ResolverController.h
@@ -26,7 +26,7 @@
     virtual ~ResolverController() {};
 
     int setDefaultInterface(const char* iface);
-    int setInterfaceDnsServers(const char* iface, const char * domains, char** servers,
+    int setInterfaceDnsServers(const char* iface, const char * domains, const char** servers,
             int numservers);
     int setInterfaceAddress(const char* iface, struct in_addr* addr);
     int flushDefaultDnsCache();