Allow dependencies to still install

Oops bug.

Library/Homebrew/cmd/upgrade.rb

@@ -63,7 +63,7 @@ module Homebrew extend self
 
     installer.install
     installer.caveats
-    installer.finish # includes link step
+    installer.finish
   rescue CannotInstallFormulaError => e
     onoe e
   rescue BuildError => e
@@ -71,7 +71,7 @@ module Homebrew extend self
     puts
   ensure
     # restore previous installation state if build failed
-    outdated_keg.link if outdated_keg and not f.linked_keg.directory?
+    outdated_keg.link if outdated_keg and not f.installed? rescue nil
   end
 
 end

Library/Homebrew/formula_installer.rb

@@ -91,14 +91,19 @@ class FormulaInstaller
   end
 
   def install_dependency dep
+    outdated_keg = Keg.new(dep.linked_keg.realpath) rescue nil
+
     fi = FormulaInstaller.new dep
     fi.ignore_deps = true
     fi.show_header = false
     oh1 "Installing #{f} dependency: #{dep}"
+    outdated_keg.unlink if outdated_keg
     fi.install
-    Keg.new(dep.linked_keg.realpath).unlink if dep.linked_keg.directory?
     fi.caveats
     fi.finish
+  ensure
+    # restore previous installation state if build failed
+    outdated_keg.link if outdated_keg and not dep.installed? rescue nil
   end
 
   def caveats