shill: Almost complete support for terminating dhcpcd.

BUG=chromium-os:16365,chromium-os:16013
TEST=unit tests

Change-Id: I00a46e8364fc4de3cc48ef72c1b0a9a88e95e6a0
Reviewed-on: http://gerrit.chromium.org/gerrit/2435
Tested-by: Darin Petkov <petkov@chromium.org>
Reviewed-by: Chris Masone <cmasone@chromium.org>
diff --git a/dhcp_provider.cc b/dhcp_provider.cc
index c506a77..163b1ca 100644
--- a/dhcp_provider.cc
+++ b/dhcp_provider.cc
@@ -43,12 +43,12 @@
   return it->second;
 }
 
-void DHCPProvider::BindPID(unsigned int pid, DHCPConfigRefPtr config) {
+void DHCPProvider::BindPID(int pid, DHCPConfigRefPtr config) {
   VLOG(2) << __func__ << " pid: " << pid;
   configs_[pid] = config;
 }
 
-void DHCPProvider::UnbindPID(unsigned int pid) {
+void DHCPProvider::UnbindPID(int pid) {
   VLOG(2) << __func__ << " pid: " << pid;
   configs_.erase(pid);
 }