qemu: Introduce VIR_ERR_DEVICE_MISSING

Add new error code to be able to allow consumers (such as Nova) to be
able to key of a specific error code rather than needing to search the
error message."
Signed-off-by: NChen Hanxiao <chenhanxiao@gmail.com>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>

include/libvirt/virterror.h

@@ -320,6 +320,7 @@ typedef enum {
     VIR_ERR_AGENT_UNSYNCED = 97,        /* guest agent replies with wrong id
                                            to guest-sync command (DEPRECATED)*/
     VIR_ERR_LIBSSH = 98,                /* error in libssh transport driver */
+    VIR_ERR_DEVICE_MISSING = 99,        /* fail to find the desired device */
 } virErrorNumber;
 
 /**

src/util/virerror.c

@@ -1453,6 +1453,12 @@ virErrorMsg(virErrorNumber error, const char *info)
             else
                 errmsg = _("libssh transport error: %s");
             break;
+        case VIR_ERR_DEVICE_MISSING:
+            if (info == NULL)
+                errmsg = _("device not found");
+            else
+                errmsg = _("device not found: %s");
+            break;
     }
     return errmsg;
 }