Removed misleading code from RSQLUtility - unused operator '=li=' (#1030)

Signed-off-by: Sergey Gerasimov <sergey.gerasimov@devolo.de>

hawkbit-repository/hawkbit-repository-jpa/src/main/java/org/eclipse/hawkbit/repository/jpa/rsql/RSQLUtility.java

@@ -153,7 +153,6 @@ public final class RSQLUtility {
         try {
             LOGGER.debug("parsing rsql string {}", rsql);
             final Set<ComparisonOperator> operators = RSQLOperators.defaultOperators();
-            operators.add(new ComparisonOperator("=li=", false));
             return new RSQLParser(operators).parse(rsql);
         } catch (final IllegalArgumentException e) {
             throw new RSQLParameterSyntaxException("rsql filter must not be null", e);