Fix a syntax error

Also uses a prettier syntax for setting the filename (ternary operators
are hard to read).

Author: egypt

modules/exploits/windows/smb/psexec.rb

@@ -83,7 +83,7 @@ def initialize(info = {})
 			[
 				OptBool.new('DB_REPORT_AUTH', [true, "Report an auth_note upon a successful connection", true]),
 				OptBool.new('MOF_UPLOAD_METHOD', [true, "Use WBEM instead of RPC, ADMIN$ share will be mandatory. ( Not compatible with Vista+ )", false]),
-				OptString.new('SERVICE_FILENAME', [false, "Filename to to be used on target for the service binary",nil)
+				OptString.new('SERVICE_FILENAME', [false, "Filename to to be used on target for the service binary",nil])
 			], self.class)
 	end
 
@@ -125,7 +125,7 @@ def exploit
 			report_auth_info(report_hash)
 		end
 
-		filename = datastore['SERVICE_FILENAME'] ? datastore['SERVICE_FILENAME'] : rand_text_alpha(8) + ".exe"
+		filename = datastore['SERVICE_FILENAME'] || "#{rand_text_alpha(8)}.exe"
 
 		if datastore['MOF_UPLOAD_METHOD']
 			# payload as exe