release ref on failing connectTCP

fix #115

tests/issue-115-connect-fail-leak.d

@@ -0,0 +1,22 @@
+/+ dub.sdl:
+	name "test"
+	dependency "vibe-core" path=".."
++/
+module test;
+
+import vibe.core.core;
+import vibe.core.log;
+import vibe.core.net;
+
+void main()
+{
+	foreach (_; 0 .. 20) {
+		TCPConnection conn;
+		try {
+			conn = connectTCP("127.0.0.1", 16565);
+			logError("Connection: %s", conn);
+			conn.close();
+			assert(false, "Didn't expect TCP connection on port 16565 to succeed");
+		} catch (Exception) { }
+	}
+}