fshttp: add --expect-continue-timeout default 1s - fixes #3835

Before this change the expect/continue timeout was set to
--conntimeout which was 60s by default which is too long to wait.

This was noticed when using s3 with a proxy which apparently didn't
support expect / continue properly.

Set --expect-continue-timeout 0 to disable expect/continue.

fs/config.go

@@ -54,6 +54,7 @@ type ConfigInfo struct {
 	Transfers              int
 	ConnectTimeout         time.Duration // Connect timeout
 	Timeout                time.Duration // Data channel timeout
+	ExpectContinueTimeout  time.Duration
 	Dump                   DumpFlags
 	InsecureSkipVerify     bool // Skip server certificate verification
 	DeleteMode             DeleteMode
@@ -121,6 +122,7 @@ func NewConfig() *ConfigInfo {
 	c.Transfers = 4
 	c.ConnectTimeout = 60 * time.Second
 	c.Timeout = 5 * 60 * time.Second
+	c.ExpectContinueTimeout = 1 * time.Second
 	c.DeleteMode = DeleteModeDefault
 	c.MaxDelete = -1
 	c.LowLevelRetries = 10