Use own format to specify encryption algorithm

... instead of using the one from from osmo vty directly.

This way we avoid having multiple word attribute value and we can skip
using quotes in the conf files.

Change-Id: I5265cc9990dd5e99dba1f6262b3a8c597a3e958d
diff --git a/suites/aoip_encryption/register_a5_0_authreq.py b/suites/aoip_encryption/register_a5_0_authreq.py
index 051f5e2..114c628 100755
--- a/suites/aoip_encryption/register_a5_0_authreq.py
+++ b/suites/aoip_encryption/register_a5_0_authreq.py
@@ -11,8 +11,8 @@
 
 print('start network...')
 msc.set_authentication(True)
-msc.set_encryption('a5 0')
-bsc.set_encryption('a5 0')
+msc.set_encryption('a5_0')
+bsc.set_encryption('a5_0')
 hlr.start()
 stp.start()
 msc.start()