Don't count --install as a valid brew pull URL.

We were checking that at least one URL argument was added but
the --install parameter was also counted in that.

Library/Contributions/examples/brew-pull.rb

@@ -3,16 +3,16 @@
 
 require 'utils.rb'
 
-if ARGV.empty?
-  puts 'This command requires at least one URL argument'
-  exit 1
-end
-
 if ARGV.include? '--install'
   ARGV.delete '--install'
   install = true
 end
 
+if ARGV.empty?
+  puts 'This command requires at least one URL argument'
+  exit 1
+end
+
 HOMEBREW_REPOSITORY.cd do
   ARGV.each do|arg|
     # This regex should work, if it's too precise, feel free to fix it.