Allow drmserver to unlink old socket file.

Change-Id: I35728c4f058fa9aeb51a7960395759590e20b083
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

drmserver.te

@@ -34,6 +34,8 @@ allow drmserver apk_data_file:dir rw_dir_perms;
 type_transition drmserver apk_data_file:sock_file drmserver_socket;
 allow drmserver drmserver_socket:sock_file create_file_perms;
 allow drmserver tee:unix_stream_socket connectto;
+# Delete old socket file if present.
+allow drmserver apk_data_file:sock_file unlink;
 
 # After taking a video, drmserver looks at the video file.
 r_dir_file(drmserver, media_rw_data_file)