Trying to run electrs in regtest causes a panic

[yancyribbens]

Currently I get the following panic when running regtest instead of liquidregtest

2019-10-13T15:50:38.595+00:00 - ERROR - server failed: Error: failed to parse header 0000002006226e46111a0b59caaf126043eb5bbf28c34f3a5e332a1fc7b2b73cf188910f9bea88ddd5c9a0a14108f68fcce3eace64e7310c3dda2aa57e69257c5c81e641c947a35dffff7f2001000000
electrs      | Caused by: parse failed: data not consumed entirely when explicitly deserializing
electrs      | 
electrs      | electrs exited with code 1

to reproduce:

1. use the following .env

RELEASE=elements-0.18.1.1
CHAIN=regtest
DAEMON_RPC=18443

2. docker exec -it elements /bin/bash
3. create a new address with ecli getnewaddress
4. create some test blocks with ecli generatetoaddress 10 <the address from step 3>