Fix log_level in test

Author: Watson1978

test/helper.rb

@@ -81,4 +81,5 @@ def verify_gc_compaction
 prepare_keyspace
 prepare_table
 
-Ilios::Cassandra.log_level(Ilios::Cassandra::LOG_TRACE)
+$default_test_log_level = Ilios::Cassandra::LOG_TRACE
+Ilios::Cassandra.log_level($default_test_log_level)

test/test_cassandra.rb

@@ -3,6 +3,10 @@
 require_relative 'helper'
 
 class CassandraTest < Minitest::Test
+  def teardown
+    Ilios::Cassandra.log_level($default_test_log_level)
+  end
+
   def test_log_level
     assert_raises(TypeError) { Ilios::Cassandra.log_level(Object.new) }