Allow dumpstate to run ss.

(cherry picked from commit 63c7ad6e)

Bug: 23113288
Test: see http://ag/1476096
Change-Id: I3beb21f1af092c93eceb3d5115f823c1b993727d

dumpstate.te

@@ -141,6 +141,9 @@ control_logd(dumpstate)
 allow dumpstate net_data_file:dir search;
 allow dumpstate net_data_file:file r_file_perms;
 
+# List sockets via ss.
+allow dumpstate self:netlink_tcpdiag_socket { create_socket_perms nlmsg_read };
+
 # Access /data/tombstones.
 allow dumpstate tombstone_data_file:dir r_dir_perms;
 allow dumpstate tombstone_data_file:file r_file_perms;