use full target_path

Author: timwr

lib/rex/post/meterpreter/client_core.rb

@@ -257,7 +257,7 @@ def load_library(opts)
         end
 
         library_path = "ext#{rand(1000000)}.#{suffix}"
-        target_path  = library_path
+        target_path  = "/tmp/#{library_path}"
       end
     end