Merge pull request #2728 from SvenDowideit/docker-import-doc

re-word the help for docker import to make it clear that this will be an empty image containing only the files in the tar file

commands.go

@@ -905,7 +905,7 @@ func (cli *DockerCli) CmdKill(args ...string) error {
 }
 
 func (cli *DockerCli) CmdImport(args ...string) error {
-	cmd := cli.Subcmd("import", "URL|- [REPOSITORY[:TAG]]", "Create a new filesystem image from the contents of a tarball(.tar, .tar.gz, .tgz, .bzip, .tar.xz, .txz).")
+	cmd := cli.Subcmd("import", "URL|- [REPOSITORY[:TAG]]", "Create an empty filesystem image and import the contents of the tarball (.tar, .tar.gz, .tgz, .bzip, .tar.xz, .txz) into it, then optionally tag it.")
 
 	if err := cmd.Parse(args); err != nil {
 		return nil

docs/sources/commandline/cli.rst

@@ -558,7 +558,8 @@ Displaying image hierarchy
 
     Usage: docker import URL|- [REPOSITORY[:TAG]]
 
-    Create a new filesystem image from the contents of a tarball
+    Create an empty filesystem image and import the contents of the tarball 
+    (.tar, .tar.gz, .tgz, .bzip, .tar.xz, .txz) into it, then optionally tag it.
 
 At this time, the URL must start with ``http`` and point to a single
 file archive (.tar, .tar.gz, .tgz, .bzip, .tar.xz, .txz) containing a