Remove redundant check for 0 and add addPermit test case

Signed-off-by: maddie-boisvert <maddie.boisvert@gmail.com>

redisson/src/main/java/org/redisson/RedissonPermitExpirableSemaphore.java

@@ -719,9 +719,6 @@ public class RedissonPermitExpirableSemaphore extends RedissonExpirable implemen
                     "return 0;" +
                 "end;" +
                 "local delta = tonumber(ARGV[1]) - maximum; " +
-                "if (delta == 0) then " +
-                    "return 0;" +
-                "end;" +
                 "redis.call('incrby', KEYS[1], delta); " +
                 "redis.call('publish', KEYS[2], ARGV[1]); " +
                 "return delta;",

redisson/src/test/java/org/redisson/RedissonPermitExpirableSemaphoreTest.java

@@ -247,6 +247,8 @@ public class RedissonPermitExpirableSemaphoreTest extends BaseConcurrentTest {
         assertThat(s.availablePermits()).isEqualTo(15);
         s.addPermits(-10);
         assertThat(s.availablePermits()).isEqualTo(5);
+        s.addPermits(-10);
+        assertThat(s.availablePermits()).isEqualTo(-5);
     }
     
     @Test