Split bottle logic.

Fixes Homebrew/homebrew#8805.

Library/Homebrew/formula.rb

@@ -57,6 +57,10 @@ class Formula
     return false
   end
 
+  def bottle_up_to_date?
+    !bottle_url.nil? && Pathname.new(bottle_url).version == version
+  end
+
   def explicitly_requested?
     # `ARGV.formulae` will throw an exception if it comes up with an empty list.
     # FIXME: `ARGV.formulae` shouldn't be throwing exceptions, see issue #8823

Library/Homebrew/formula_installer.rb

@@ -15,8 +15,7 @@ class FormulaInstaller
     @f = ff
     @show_header = true
     @ignore_deps = ARGV.include? '--ignore-dependencies' || ARGV.interactive?
-    @install_bottle = !ff.bottle_url.nil? && !ARGV.build_from_source? &&
-                      Pathname.new(ff.bottle_url).version == ff.version
+    @install_bottle = !ARGV.build_from_source? && ff.bottle_up_to_date?
   end
 
   def install