Revert "Change content-type for json stream to application/x-json-stream."

This reverts commit 10ab2089ce.

Conflicts:
	api/client/utils.go
	docs/sources/reference/api/docker_remote_api.md

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jess@docker.com> (github: jfrazelle)

docs/sources/reference/api/docker_remote_api.md

@@ -41,22 +41,6 @@ You can still call an old version of the API using
 
 ### What's new
 
-`POST /build`
-`GET /events`
-
-**New!**
-Now has header: `Content-Type: application/x-json-stream`.
-
-`POST /containers/(id)/exec`
-
-**New!**
-Setup an exec command in a running container `id`.
-
-`POST /exec/(id)/start`
-
-**New!**
-Start an exec command.
-
 ## v1.14
 
 ### Full Documentation
@@ -97,7 +81,7 @@ the `tag` parameter at the same time will return an error.
 The `HostConfig.Links` field is now filled correctly
 
 **New!**
-`Sockets` parameter added to the `/info` endpoint listing all the sockets the
+`Sockets` parameter added to the `/info` endpoint listing all the sockets the 
 daemon is configured to listen on.
 
 `POST /containers/(name)/start`
@@ -425,7 +409,7 @@ Builder (/build):
    intermediary buffers
  - Simpler, less memory usage, less disk usage and faster
 
-> **Warning**:
+> **Warning**: 
 > The /build improvements are not reverse-compatible. Pre 1.3 clients will
 > break on /build.