bts: Run everything over 127.0.0.1

When the test is executed outside of docker, having to manage all
those different IP addresses while manually starting programs can be
quite cumbersome.  Let's just run everything over localhost, like
we always do with other tests.

Now the only cumbersome command to start is trxcon, as it defaults to
only one TRX and adding additional TRX is rather complicated:

./fake_trx.py --trx TRX1@127.0.0.1:5700/1 --trx TRX2@127.0.0.1:5700/2 --trx TRX3@127.0.0.1:5700/3

Change-Id: Iea8519685da7d73696ce9cc2541e93c45c099828
diff --git a/bts/osmo-bts.cfg b/bts/osmo-bts.cfg
index 0e4cdf2..b7282da 100644
--- a/bts/osmo-bts.cfg
+++ b/bts/osmo-bts.cfg
@@ -2,7 +2,7 @@
 ! OsmoBTS (0.4.0.446-e0fb) configuration saved from vty
 !!
 !
-log gsmtap 127.0.0.10
+log gsmtap 127.0.0.1
  logging level set-all debug
  logging filter all 1
 !
@@ -25,15 +25,15 @@
 !
 line vty
  no login
- bind 127.0.0.20
+ bind 127.0.0.1
 !
 e1_input
  e1_line 0 driver ipa
  e1_line 0 port 0
  no e1_line 0 keepalive
 phy 0
- osmotrx ip local 127.0.0.20
- osmotrx ip remote 127.0.0.21
+ osmotrx ip local 127.0.0.1
+ osmotrx ip remote 127.0.0.1
  osmotrx fn-advance 20
  osmotrx rts-advance 5
  instance 0
@@ -85,4 +85,4 @@
   power-ramp step-interval 1
   phy 0 instance 3
 ctrl
- bind 127.0.0.20
+ bind 127.0.0.1