Merge pull request #2161 from paddor/master

avoid TypeError when exiting

Author: JonRowe

lib/rspec/core/rake_task.rb

@@ -81,7 +81,7 @@ def run_task(verbose)
 
         return unless fail_on_error
         $stderr.puts "#{command} failed" if verbose
-        exit $?.exitstatus
+        exit $?.exitstatus || 1
       end
 
     private