Merge pull request #7106 from hashicorp/revert_docker_changes

docker: user /bin/sh by default

builder/docker/config.go

@@ -73,7 +73,7 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 
 	// Defaults
 	if len(c.RunCommand) == 0 {
-		c.RunCommand = []string{"-d", "-i", "-t", "{{.Image}}", "/bin/bash"}
+		c.RunCommand = []string{"-d", "-i", "-t", "--entrypoint=/bin/sh", "--", "{{.Image}}"}
 	}
 
 	// Default Pull if it wasn't set

website/source/docs/builders/docker.html.md

@@ -210,7 +210,7 @@ You must specify (only) one of `commit`, `discard`, or `export_path`.
 
 -   `run_command` (array of strings) - An array of arguments to pass to
     `docker run` in order to run the container. By default this is set to
-    `["-d", "-i", "-t", "{{.Image}}", "/bin/bash"]`. As you can see, you have a
+    `["-d", "-i", "-t", "{{.Image}}", "/bin/sh"]`. As you can see, you have a
     couple template variables to customize, as well.
 
 -   `volumes` (map of strings to strings) - A mapping of additional volumes to