Fix a typo

Author: kou

lib/rubygems-requirements-system/platform/base.rb

@@ -147,7 +147,7 @@ def run_command_line(package, action, command_line)
 
         unless succeeded
           escaped_command_line = command_line.collect do |part|
-            Shellwobrds.escape(part)
+            Shellwords.escape(part)
           end
           @ui.error("#{prefix}: Failed.")
           @ui.error("Run the following command " +