download checks the content-length when the --size flag is omitted

[bcomnes]

Right now, the download assertion always investigates the Content-length, even when the --size argument is omitted:

bret-mbr:.ssh bret$ bork do ok download authorized_keys "https://github.com/bcomnes.keys"
conflict (upgradable): download authorized_keys https://github.com/bcomnes.keys
expected size:  bytes
received size:  bytes

== Warning! Assertion: download authorized_keys https://github.com/bcomnes.keys
Attempting to satisfy has resulted in a conflict.  Satisfying this may overwrite data.
Do you want to continue? (yes/no) yes
Resolving conflict...
verifying : download authorized_keys https://github.com/bcomnes.keys
*  failed
conflict (upgradable)                                             
expected size:  bytes
received size:  bytes

I'm still trying to track this one down, but if $(arguments get size); then is always evaluating true for some reason.