Revert Library/Homebrew/cmd/install.rb to 4b320eec.

* Fix problem when install exception got swallow and reinstall thinks it
  succeeded.

Library/Homebrew/cmd/install.rb

@@ -19,7 +19,13 @@ module Homebrew extend self
     end unless ARGV.force?
 
     perform_preinstall_checks
-    ARGV.formulae.each { |f| install_formula(f) }
+    ARGV.formulae.each do |f|
+      begin
+        install_formula(f)
+      rescue CannotInstallFormulaError => e
+        ofail e.message
+      end
+    end
   end
 
   def check_ppc
@@ -80,7 +86,6 @@ module Homebrew extend self
     # another formula. In that case, don't generate an error, just move on.
   rescue FormulaAlreadyInstalledError => e
     opoo e.message
-  rescue CannotInstallFormulaError => e
-    ofail e.message
+  # Ignore CannotInstallFormulaError and let caller handle it.
   end
 end