data tree CHANGE to clarify purpose, rename data path types

Clarify how the paths generated by lyd_path() can be used.

Fixes #1317
diff --git a/src/log.c b/src/log.c
index 5208c94..8dde303 100644
--- a/src/log.c
+++ b/src/log.c
@@ -429,7 +429,7 @@
         LY_CHECK_ERR_RET(!(*path), LOGMEM(ctx), LY_EMEM);
         break;
     case LY_VLOG_LYD:
-        *path = lyd_path(elem, LYD_PATH_LOG, NULL, 0);
+        *path = lyd_path(elem, LYD_PATH_STD, NULL, 0);
         LY_CHECK_ERR_RET(!(*path), LOGMEM(ctx), LY_EMEM);
         break;
     default: