Allow created containers to be killed

Signed-off-by: Mrunal Patel <[email protected]>

Author: mrunalp

runtime.md

@@ -123,7 +123,7 @@ This operation MUST generate an error if `process` was not set.
 `kill <container-id> <signal>`
 
 This operation MUST [generate an error](#errors) if it is not provided the container ID.
-Attempting to send a signal to a container that is not running MUST have no effect on the container and MUST [generate an error](#errors).
+Attempting to send a signal to a container that is not running or not created MUST have no effect on the container and MUST [generate an error](#errors).
 This operation MUST send the specified signal to the process in the container.
 
 ### <a name="runtimeDelete" />Delete