transaction sign always tries to connect to upstream

[splix]

emerald --chain=morden transaction \
  0x3fdc12e77912620c907a1c65a076b38b307968fd \
  0x86da613e694670fb3a61ce0a565ab40bb27ed60d \
  0x100 \
  --nonce=0x1 --gas=0x2100 --gas-price=0x15115
Enter passphrase:

[ERROR]	Command execution error: http://127.0.0.1:8545/: Connection refused (os error 61)

If upstream is not specified it should generate an offline transaction (i.e. put to stdout) instead of sending it right now