Update wp_slideshowgallery_upload.rb

Variable on line 67 needs to be changed to "user" from "username" which was undefined and causing error during exploit execution.

[-] Exploit failed: NameError undefined local variable or method `username' for #<Msf::Modules::Mod6578706c6f69742f756e69782f7765626170702f77705f736c69646573686f7767616c6c6572795f75706c6f6164::MetasploitModule:0x0055c61ab093f8>

After changing the incorrect variable name from "username" to "user", the exploit completes.

modules/exploits/unix/webapp/wp_slideshowgallery_upload.rb

@@ -64,7 +64,7 @@ class MetasploitModule < Msf::Exploit::Remote
       print_error("Unable to login as #{user}")
       return
     end
-    store_valid_credential(user: username, private: password, proof: cookie)
+    store_valid_credential(user: user, private: password, proof: cookie)
 
     print_status("Trying to upload payload")
     filename = "#{rand_text_alpha_lower(8)}.php"