sgsn: Restructure the 'update-subscriber' command

This patch drops the following commands:

 - update-subscriber imsi IMSI insert authorized <0-1>
 - update-subscriber imsi IMSI commit

since they are already covered by the 'update-location-result'
sub-command, except that this command doesn't create an new entry if
none is found with the given IMSI.

It adds the following command:

 - update-subscriber imsi IMSI create

which can be used to create a new entry.

Sponsored-by: On-Waves ehf
diff --git a/openbsc/tests/vty_test_runner.py b/openbsc/tests/vty_test_runner.py
index a3cb9e5..31fadf1 100644
--- a/openbsc/tests/vty_test_runner.py
+++ b/openbsc/tests/vty_test_runner.py
@@ -760,14 +760,14 @@
         self.vty.enable()
         res = self.vty.command('show subscriber cache')
         self.assert_(res.find('1234567890') < 0)
-        self.assertTrue(self.vty.verify('update-subscriber imsi 1234567890 insert authorized 1', ['']))
+        self.assertTrue(self.vty.verify('update-subscriber imsi 1234567890 create', ['']))
+        res = self.vty.command('show subscriber cache')
+        self.assert_(res.find('1234567890') >= 0)
+        self.assert_(res.find('Authorized: 0') >= 0)
+        self.assertTrue(self.vty.verify('update-subscriber imsi 1234567890 update-location-result ok', ['']))
         res = self.vty.command('show subscriber cache')
         self.assert_(res.find('1234567890') >= 0)
         self.assert_(res.find('Authorized: 1') >= 0)
-        self.assertTrue(self.vty.verify('update-subscriber imsi 1234567890 insert authorized 0', ['']))
-        res = self.vty.command('show subscriber cache')
-        self.assert_(res.find('Authorized: 0') >= 0)
-        self.assertTrue(self.vty.verify('update-subscriber imsi 1234567890 commit', ['']))
         self.assertTrue(self.vty.verify('update-subscriber imsi 1234567890 cancel', ['']))
         res = self.vty.command('show subscriber cache')
         self.assert_(res.find('1234567890') < 0)