deps: fix --1 output

Fixes Homebrew/homebrew#17550.
Closes Homebrew/homebrew#19668.

Library/Homebrew/cmd/deps.rb

@@ -1,7 +1,7 @@
 require 'formula'
 
 def recursive_deps_tree f, level
-  f.deps.each do |dep|
+  f.deps.default.each do |dep|
     puts "|  "*(level-1)+"|- "+dep.to_s
     recursive_deps_tree(Formula.factory(dep), level+1)
   end
@@ -27,7 +27,7 @@ module Homebrew extend self
     else
       raise FormulaUnspecifiedError if ARGV.named.empty?
       all_deps = ARGV.formulae.map do |f|
-        ARGV.one? ? f.deps : f.recursive_dependencies
+        ARGV.one? ? f.deps.default : f.recursive_dependencies
       end.intersection.map(&:name)
       all_deps.sort! unless ARGV.include? "-n"
       puts all_deps