Change dnsmasq input command argument separator

Heretofore netd issued commands to dnsmasq over a stdin channel
using ":" as an argument separator. This make it very complicated
to issue commands that involve IPv6 addresses.

This changes the separator from ":" to "|".

Additionally:

    - Pass DHCP range string literals through to startTethering(),
      still performing string literal to IPv4 address validation.

Bug: 9580643
Change-Id: I210daf311a4c3d84dae3ed054b92c9fa399a791f
diff --git a/server/TetherController.h b/server/TetherController.h
index 91ffb9c..a2ac793 100644
--- a/server/TetherController.h
+++ b/server/TetherController.h
@@ -44,7 +44,7 @@
     bool disableForwarding(const char* requester);
     size_t forwardingRequestCount();
 
-    int startTethering(int num_addrs, struct in_addr* addrs);
+    int startTethering(int num_addrs, char **dhcp_ranges);
     int stopTethering();
     bool isTetheringStarted();