chore(build): Get rel vsn fallback (#4339)

src/emqx_app.erl

@@ -70,18 +70,15 @@ get_description() ->
         Str -> string:strip(Str, both, $\n)
     end.
 
--ifdef(TEST).
-%% When testing, the 'cover' compiler stripps aways compile info
-get_release() -> release_in_macro().
--else.
-%% Otherwise print the build number,
-%% which may have a git commit in its suffix.
 get_release() ->
-    {_, Vsn} = lists:keyfind(emqx_vsn, 1, ?MODULE:module_info(compile)),
-    VsnStr = release_in_macro(),
-    1 = string:str(Vsn, VsnStr), %% assert
-    Vsn.
--endif.
+    case lists:keyfind(emqx_vsn, 1, ?MODULE:module_info(compile)) of
+        false ->    %% For TEST build or depedency build.
+            release_in_macro();
+        {_, Vsn} -> %% For emqx release build
+            VsnStr = release_in_macro(),
+            1 = string:str(Vsn, VsnStr), %% assert
+            Vsn
+    end.
 
 release_in_macro() ->
     element(2, ?EMQX_RELEASE).