Introduce support for XOR-2G algorithm

So far we supported a "xor" algorithm in osmo-hlr, without specifying
whether it's the XOR-3G or the (different) XOR-2G algorithm.

Furthermore, it was buggy in the sense that it permitted the XOR[-3G]
for 2G authentication data in the database.

This patch
* renames existing "xor" to "xor-3g"
* disallows "xor-3g" usage with 2G authentication data
* introduces support for XOR-2G as "xor-2g" in the VTY

Change-Id: I039a1f84fda54a908a82fe621e7fd078cb85e4c6
Depends: libosmocore.git I0ee0565382c1e4515d44ff9b1752685c0a66ae39
diff --git a/tests/db_upgrade/db_upgrade_test.ok b/tests/db_upgrade/db_upgrade_test.ok
index 0a45f7c..ce5b17c 100644
--- a/tests/db_upgrade/db_upgrade_test.ok
+++ b/tests/db_upgrade/db_upgrade_test.ok
@@ -12,7 +12,7 @@
 algo_id_2g|ki|subscriber_id
 1|BeefedCafeFaceAcedAddedDecadeFee|1
 2|33333333333333333333333333333333|4
-4|55555555555555555555555555555555|6
+6|55555555555555555555555555555555|6
 
 Table: auc_3g
 name|type|notnull|dflt_value|pk
@@ -100,7 +100,7 @@
 algo_id_2g|ki|subscriber_id
 1|BeefedCafeFaceAcedAddedDecadeFee|1
 2|33333333333333333333333333333333|4
-4|55555555555555555555555555555555|6
+6|55555555555555555555555555555555|6
 
 Table: auc_3g
 name|type|notnull|dflt_value|pk