tools: rework on vm ops

There are some problems to use VM operations in a deamon process,
such as Acrnd.  the list_vm() does not return VM informations, it
just print VM information to stdio, so we have get_vm_list()
to get VM list head vmngr_head; get_vm_list() always creates a
new fresh vm list every time, and must use put_vm_list() to delete
old list. So Acrnd need to create and destroy vm list frequently.
In fact we just need the vmngr_head to be an extern variable. And
to make it refreshable.We can insert new VMs, remove dead ones,
and update their state.

Reviewed-by: Yan Like <like.yan@intel.com>
Signed-off-by: Tao Yuhong <yuhong.tao@intel.com>

tools/acrn-manager/acrn_mngr.c

@@ -17,12 +17,6 @@
 #include "mevent.h"
 #include "acrn_mngr.h"
 
-#ifdef MNGR_DEBUG
-#define pdebug()	fprintf(stderr, "%s %d\n", __FUNCTION__, __LINE__)
-#else
-#define pdebug()	while(0){}
-#endif
-
 /* helpers */
 /* Check if @path is a directory, and create if not exist */
 static int check_dir(const char *path)