Change targetr to target to fix small typo bug on one failure

The target object seems to have a typo where it is referred to as
“targetr” which I’d guess isn’t exactly what we’d like to do in this
case. So, I’ve changed that to “target” in order to work.

So, I’ve simply fixed that small typo.

modules/exploits/windows/browser/ms07_017_ani_loadimage_chunksize.rb

@@ -494,7 +494,7 @@ def generate_ani(payload, target)
       ].pack('v')
 
     else
-      fail_with(Failure::NoTarget, "Unknown target #{targetr['Method']}")
+      fail_with(Failure::NoTarget, "Unknown target #{target['Method']}")
     end
 
     # Build the ANI file