Incorrect erroring when command is not available in container

[friism]

For example, the busybox image doesn't have bash (it does have sh). If started with command that's not available, we should return a clean error to that effect. Example:

docker -H "npipe:////./pipe//docker_lcow" run -ti busybox
 bash
C:\Program Files\Docker\Docker\Resources\bin\docker.exe: Error response from daemon: container 8693b3b051b30d36c7fe19589746b46064168d8466b43c36ded2ea4139a80541 encountered an error during CreateProcess: failure in a Windows system call: Unspecified error (0x80004005) extra info: {"CommandArgs":["bash"],"WorkingDirectory":"/","Environment":{"HOSTNAME":"8693b3b051b3","PATH":"/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin","TERM":"xterm"},"EmulateConsole":true,"CreateStdInPipe":true,"CreateStdOutPipe":true,"ConsoleSize":
[snip]

For comparison:

docker run -ti busybox bash
C:\Program Files\Docker\Docker\Resources\bin\docker.exe: Error response from daemon: oci runtime error: container_linux.go:265: starting container process caused "exec: \"bash\": executable file not found in $PATH".

This is with a (otherwise) working system set up like this: docker run -ti busybox bash
C:\Program Files\Docker\Docker\Resources\bin\docker.exe: Error response from daemon: oci runtime error: container_linux.go:265: starting container process caused "exec: "bash": executable file not found in $PATH".