init: don't log in expand_props directly

It's better to pass the error message to the caller to determine how
best to print the error.

Test: build
Change-Id: Id8857c459df2f26c031650166609608d20e4d051
diff --git a/init/import_parser.cpp b/init/import_parser.cpp
index c72b7d6..1a43508 100644
--- a/init/import_parser.cpp
+++ b/init/import_parser.cpp
@@ -29,15 +29,14 @@
         return Error() << "single argument needed for import\n";
     }
 
-    std::string conf_file;
-    bool ret = expand_props(args[1], &conf_file);
-    if (!ret) {
-        return Error() << "error while expanding import";
+    auto conf_file = ExpandProps(args[1]);
+    if (!conf_file) {
+        return Error() << "Could not expand import: " << conf_file.error();
     }
 
-    LOG(INFO) << "Added '" << conf_file << "' to import list";
+    LOG(INFO) << "Added '" << *conf_file << "' to import list";
     if (filename_.empty()) filename_ = filename;
-    imports_.emplace_back(std::move(conf_file), line);
+    imports_.emplace_back(std::move(*conf_file), line);
     return {};
 }