Don't fail ReadArgs if length to parse is 0

Test: recovery component tests pass
Change-Id: I0946ba498d845ec552ae7e4c79dc94618b2fdf6d
diff --git a/edify/expr.cpp b/edify/expr.cpp
index 2b7fd7a..54ab332 100644
--- a/edify/expr.cpp
+++ b/edify/expr.cpp
@@ -357,7 +357,7 @@
     if (args == nullptr) {
         return false;
     }
-    if (len == 0 || start + len > argv.size()) {
+    if (start + len > argv.size()) {
         return false;
     }
     for (size_t i = start; i < start + len; ++i) {