Utils: add IsDotOrDotDot() and use it in the appropriate places

Change-Id: I704522b26acfb3e7c423d9a14d69ede513b50482
diff --git a/MoveStorage.cpp b/MoveStorage.cpp
index 2447cce..3f636a2 100644
--- a/MoveStorage.cpp
+++ b/MoveStorage.cpp
@@ -70,9 +70,7 @@
     bool found = false;
     struct dirent* ent;
     while ((ent = readdir(dirp.get())) != NULL) {
-        if ((!strcmp(ent->d_name, ".")) || (!strcmp(ent->d_name, ".."))) {
-            continue;
-        }
+        if (IsDotOrDotDot(*ent)) continue;
         auto subdir = path + "/" + ent->d_name;
         found |= pushBackContents(subdir, cmd, searchLevels - 1);
     }