Manually re-apply #1269

Author: michaelklishin

scripts/rabbitmq-env.bat

@@ -407,7 +407,7 @@ exit /b
 
 :filter_path
 REM Ensure ERL_LIBS begins with valid path
-IF [%ERL_LIBS%] EQU [] (
+IF "%ERL_LIBS%"=="" (
     set ERL_LIBS=%~dps1%~n1%~x1
 ) else (
     set ERL_LIBS=%ERL_LIBS%;%~dps1%~n1%~x1