Remove net_domain() from isolated_app.

isolated_app performs no direct network socket communication, so
we can remove net_domain() from it.

Change-Id: I112aa4140fd577a5ea28f7a3d62567ebabcdb48d
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

isolated_app.te

@@ -11,7 +11,6 @@
 
 type isolated_app, domain;
 app_domain(isolated_app)
-net_domain(isolated_app)
 
 # Isolated apps shouldn't be able to access the driver directly.
 neverallow isolated_app gpu_device:file { rw_file_perms execute };