apmanager: add firewall rules during run time

Use permission_broker to add firewall rules when apmanager starts.
Also remove the temporary hack in webservd upstart script for
adding firewall rules on behalf of apmanager.

BUG=chromium:450408
TEST=Verify firewall rule for UDP port 67 (DHCP port) is added
     when apmanager starts, and removed after apmanager is
     terminated.
     Run security_Firewall autotest.
CQ-DEPEND=CL:246272,CL:247141,CL:247210

Change-Id: I4b25dc753a12ff91ed68d712f096ed570e635ad8
Reviewed-on: https://chromium-review.googlesource.com/246699
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Commit-Queue: Zeping Qiu <zqiu@chromium.org>
Tested-by: Zeping Qiu <zqiu@chromium.org>
6 files changed