Fix keys leaked in TimeSeries spec

Forgot to clean up after this. Usually the `test` macro handles this,
but we needed 2 keys here and that macro only supplies 1, so we had to
do this manually.

spec/time_series_spec.cr

@@ -120,14 +120,19 @@ module Redis
     it "gets the index names for a given filter" do
       included_key = UUID.random.to_s
       excluded_key = UUID.random.to_s
-      name_label = UUID.random.to_s
-      redis.ts.create included_key, labels: { "name" => name_label, }
-      redis.ts.create excluded_key, labels: { "name" => UUID.random.to_s, }
 
-      names = redis.ts.queryindex("name=#{name_label}").as(Array)
+      begin
+        name_label = UUID.random.to_s
+        redis.ts.create included_key, labels: {"name" => name_label}
+        redis.ts.create excluded_key, labels: {"name" => UUID.random.to_s}
 
-      names.should contain included_key
-      names.should_not contain excluded_key
+        names = redis.ts.queryindex("name=#{name_label}").as(Array)
+
+        names.should contain included_key
+        names.should_not contain excluded_key
+      ensure
+        redis.unlink included_key, excluded_key
+      end
     end
   end
 end