virsh: split out virsh-nodedev.c

Another worthwhile split, needed one more public function.

* tools/virsh-nodedev.h: New file.
* tools/Makefile.am (virsh_SOURCES): Build it.
* tools/virsh-nodedev.c: Use new header.
* tools/virsh.c: Likewise.
(vshTreePrint): Export.
* tools/virsh.h (vshTreePrint): Declare.

tools/virsh.h

@@ -296,6 +296,12 @@ typedef enum {
     VSH_BYMAC  = (1 << 4),
 } vshLookupByFlags;
 
+/* Given an index, return either the name of that device (non-NULL) or
+ * of its parent (NULL if a root).  */
+typedef const char * (*vshTreeLookup)(int devid, bool parent, void *opaque);
+int vshTreePrint(vshControl *ctl, vshTreeLookup lookup, void *opaque,
+                 int num_devices, int devid);
+
 void vshPrintExtra(vshControl *ctl, const char *format, ...)
     ATTRIBUTE_FMT_PRINTF(2, 3);
 void vshDebug(vshControl *ctl, int level, const char *format, ...)