ENGINE_ctrl() had been insisting that the ENGINE supplied was already

initialised for use, but one of the useful things about ENGINE_ctrl()
is that it can be a useful way to provide settings that should be
used during initialisation. Instead, I've altered the code to insist
that the engine has a valid *structural* reference (rather than a
*functional* one).

crypto/engine/engine_err.c

@@ -154,6 +154,7 @@ static ERR_STRING_DATA ENGINE_str_reasons[]=
 {ENGINE_R_NO_CONTROL_FUNCTION            ,"no control function"},
 {ENGINE_R_NO_KEY                         ,"no key"},
 {ENGINE_R_NO_LOAD_FUNCTION               ,"no load function"},
+{ENGINE_R_NO_REFERENCE			 ,"no reference"},
 {ENGINE_R_NO_SUCH_ENGINE                 ,"no such engine"},
 {ENGINE_R_NO_UNLOAD_FUNCTION             ,"no unload function"},
 {ENGINE_R_PROVIDE_PARAMETERS             ,"provide parameters"},