1/2: Rename domain "system" to "system_server".

This is a follow-up CL to the extraction of "system_app" domain
from the "system" domain which left the "system" domain encompassing
just the system_server.

Since this change cannot be made atomically across different
repositories, it temporarily adds a typealias "server" pointing to
"system_server". Once all other repositories have been switched to
"system_server", this alias will be removed.

Change-Id: I90a6850603dcf60049963462c5572d36de62bc00
diff --git a/seapp_contexts b/seapp_contexts
index 41d3dd8..2049b8a 100644
--- a/seapp_contexts
+++ b/seapp_contexts
@@ -32,7 +32,7 @@
 # levelFrom=app or levelFrom=all is only supported for _app UIDs.
 # level may be used to specify a fixed level for any UID. 
 #
-isSystemServer=true domain=system
+isSystemServer=true domain=system_server
 user=system domain=system_app type=system_data_file
 user=bluetooth domain=bluetooth type=bluetooth_data_file
 user=nfc domain=nfc type=nfc_data_file