Scope AlaveteliDsl#login fields within signup_form
Scope AlaveteliDsl#login fields within signup_form

Fills in the first “Your e-mail:” field it finds, which could be
the sign _up_ form if the view is overridden to swap the order
of the sign in and sign up forms.

Also compacts a simple conditional on to one line.

Br3nda/alaveteli,andreicristianpetcu/alaveteli,andreicristianpetcu/alaveteli_old,Br3nda/alaveteli,4bic/alaveteli,Br3nda/alaveteli,andreicristianpetcu/alaveteli,petterreinholdtsen/alaveteli,nzherald/alaveteli,andreicristianpetcu/alaveteli_old,Br3nda/alaveteli,TEDICpy/QueremoSaber,petterreinholdtsen/alaveteli,andreicristianpetcu/alaveteli_old,petterreinholdtsen/alaveteli,andreicristianpetcu/alaveteli,nzherald/alaveteli,nzherald/alaveteli,nzherald/alaveteli,Br3nda/alaveteli,andreicristianpetcu/alaveteli_old,andreicristianpetcu/alaveteli,4bic/alaveteli,nzherald/alaveteli,petterreinholdtsen/alaveteli,TEDICpy/QueremoSaber,andreicristianpetcu/alaveteli_old,TEDICpy/QueremoSaber,4bic/alaveteli,TEDICpy/QueremoSaber,petterreinholdtsen/alaveteli,4bic/alaveteli,4bic/alaveteli,TEDICpy/QueremoSaber,andreicristianpetcu/alaveteli