Fix for crash when cancelling requests.

It seems that notifying the NSOperationQueue we're complete before we start running causes a problem resulting in a crash.

Hence, we avoid calling markAsFinished unless we're inprogress - main() will call it when we do start.

Classes/ASIHTTPRequest.m

@@ -1718,6 +1718,12 @@ - (void)failWithError:(NSError *)theError
 
     [failedRequest reportFailure];
 
+    if (!inProgress)
+    {
+        // if we're not in progress, we can't notify the queue we've finished (doing so can cause a crash later on)
+        // "markAsFinished" will be at the start of main() when we are started
+        return;
+    }
 	// markAsFinished may well cause this object to be dealloced
 	[self retain];
 	[self markAsFinished];