Make qOverloadOf unnecessary in Qt Network

In case of QtNetwork the problem mostly occurs in error handling: a signal has a very generic name 'error', and then the getter (which returns the error that also was reported by the signal) has the same name. The safest approach is to rename the getter. Changing the signal's name would silently break the code that still would compile and later fail to report errors at run-time. For each class modified we'd have to update tests, documentation and examples. Classes in questions are:

• QLocalSocket
• QAbstractSocket
• QNetworkReply
• QSslSocket