clang-error: fix clang-diagnostic-defaulted-function-deleted error

The clang-diagnostic-defaulted-function-deleted error is generated when
explicitly defaulted move assignment operator is implicitly deleted.
This commit fixes those errors.

Change-Id: Id62b89eb3b58b819799194be91516f7c5e9cadc6
Signed-off-by: Pavithra Barithaya <pavithrabarithaya07@gmail.com>
diff --git a/sync_watch.hpp b/sync_watch.hpp
index d85ac8c..f91ce29 100644
--- a/sync_watch.hpp
+++ b/sync_watch.hpp
@@ -36,7 +36,7 @@
     SyncWatch(const SyncWatch&) = delete;
     SyncWatch& operator=(const SyncWatch&) = delete;
     SyncWatch(SyncWatch&&) = default;
-    SyncWatch& operator=(SyncWatch&&) = default;
+    SyncWatch& operator=(SyncWatch&&) = delete;
 
     /** @brief dtor - remove inotify watch and close fd's
      */