split up 'if' statements that assign and test (2)

split up 'if' statements that assign and test (2)

Split 'if' statements that combine an assignment with a test.
e.g. from:

    if (!(adr = mutt_parse_adrlist(adr, buf)))

To:
    adr = mutt_parse_adrlist(adr, buf);
    if (!adr)

This makes the statements a little easier to read and debug.