Fixed issue with exists(keys), unlink, and touch (opentracing-contrib#51)

Issue found with versions 0.1.2 through 0.1.15-SNAPSHOT of this class where the expected functionality of exists(keys), unlink(keys), and touch(keys) are not met. In early versions, no error would be found, and in newer versions, sometimes and error would be found if empty keys were not allowed.

Author: jonlockwood

opentracing-redis-spring-data2/src/main/java/io/opentracing/contrib/redis/spring/data2/connection/TracingRedisConnection.java

@@ -185,7 +185,7 @@ public Boolean exists(byte[] key) {
 
  @Override
  public Long exists(byte[]... keys) {
- return helper.doInScope(RedisCommand.EXISTS, keys, connection::exists);
+ return helper.doInScope(RedisCommand.EXISTS, keys, () -> connection.exists(keys));
  }
 
  @Override
@@ -195,7 +195,7 @@ public Long del(byte[]... keys) {
 
  @Override
  public Long unlink(byte[]... keys) {
- return helper.doInScope(RedisCommand.UNLINK, keys, connection::unlink);
+ return helper.doInScope(RedisCommand.UNLINK, keys, () -> connection.unlink(keys));
  }
 
  @Override
@@ -205,7 +205,7 @@ public DataType type(byte[] key) {
 
  @Override
  public Long touch(byte[]... keys) {
- return helper.doInScope(RedisCommand.TOUCH, keys, connection::touch);
+ return helper.doInScope(RedisCommand.TOUCH, keys, () -> connection.touch(keys));
  }
 
  @Override