Fix incompatibilities with rspec 3.

Author: headius

spec/launcher_spec.rb

@@ -12,10 +12,10 @@
 
   it "should print help message" do
     args = jruby_launcher_args("-Xhelp 2>&1")
-    args.detect{|l| l =~ /JRuby Launcher usage/}.should be_true
+    args.select {|l| l =~ /JRuby Launcher usage/}.should_not be_empty
     args.should include("-X")
     args = jruby_launcher_args("-X 2>&1")
-    args.detect{|l| l =~ /JRuby Launcher usage/}.should be_true
+    args.detect {|l| l =~ /JRuby Launcher usage/}.should_not be_empty
     args.should include("-X")
   end