Do not set beta protocol flag when using v5

Driver was automatically setting beta flag when using v5 protocol which causes issues when trying to connect to Cassandra
versions that supported beta v5 like 3.11.

Patch by João Reis; reviewed by TBD for CASSGO-88

Author: joao-r-reis

control.go

@@ -204,10 +204,17 @@ func shuffleHosts(hosts []*HostInfo) []*HostInfo {
 
 // this is going to be version dependant and a nightmare to maintain :(
 var protocolSupportRe = regexp.MustCompile(`the lowest supported version is \d+ and the greatest is (\d+)$`)
+var betaProtocolRe = regexp.MustCompile(`Beta version of the protocol used \(.*\), but USE_BETA flag is unset`)
 
 func parseProtocolFromError(err error) int {
+	errStr := err.Error()
+
 	// I really wish this had the actual info in the error frame...
-	matches := protocolSupportRe.FindAllStringSubmatch(err.Error(), -1)
+	matches := betaProtocolRe.FindAllStringSubmatch(errStr, -1)
+	if len(matches) == 1 {
+		return int(highestProtocolVersionSupported - 1)
+	}
+	matches = protocolSupportRe.FindAllStringSubmatch(errStr, -1)
 	if len(matches) != 1 || len(matches[0]) != 2 {
 		if verr, ok := err.(*protocolError); ok {
 			return int(verr.frame.Header().version.version())
@@ -223,11 +230,13 @@ func parseProtocolFromError(err error) int {
 	return max
 }
 
+const highestProtocolVersionSupported = 5
+
 func (c *controlConn) discoverProtocol(hosts []*HostInfo) (int, error) {
 	hosts = shuffleHosts(hosts)
 
 	connCfg := *c.session.connCfg
-	connCfg.ProtoVersion = 5 // TODO: define maxProtocol
+	connCfg.ProtoVersion = highestProtocolVersionSupported
 
 	handler := connErrorHandlerFn(func(c *Conn, err error, closed bool) {
 		// we should never get here, but if we do it means we connected to a

frame.go

@@ -393,9 +393,6 @@ func newFramer(compressor Compressor, version byte, r *RegisteredTypes) *framer
 	if compressor != nil {
 		flags |= flagCompress
 	}
-	if version == protoVersion5 {
-		flags |= flagBetaProtocol
-	}
 
 	version &= protoVersionMask