Revert "context: inherits context cancelation and deadline from http.Request context for Go>=1.7 (#1690)" (#1736)

This reverts commit f67d7a90c4.

context.go

@@ -942,6 +942,34 @@ func (c *Context) SetAccepted(formats ...string) {
 	c.Accepted = formats
 }
 
+/************************************/
+/***** GOLANG.ORG/X/NET/CONTEXT *****/
+/************************************/
+
+// Deadline returns the time when work done on behalf of this context
+// should be canceled. Deadline returns ok==false when no deadline is
+// set. Successive calls to Deadline return the same results.
+func (c *Context) Deadline() (deadline time.Time, ok bool) {
+	return
+}
+
+// Done returns a channel that's closed when work done on behalf of this
+// context should be canceled. Done may return nil if this context can
+// never be canceled. Successive calls to Done return the same value.
+func (c *Context) Done() <-chan struct{} {
+	return nil
+}
+
+// Err returns a non-nil error value after Done is closed,
+// successive calls to Err return the same error.
+// If Done is not yet closed, Err returns nil.
+// If Done is closed, Err returns a non-nil error explaining why:
+// Canceled if the context was canceled
+// or DeadlineExceeded if the context's deadline passed.
+func (c *Context) Err() error {
+	return nil
+}
+
 // Value returns the value associated with this context for key, or nil
 // if no value is associated with key. Successive calls to Value with
 // the same key returns the same result.