Update connection_spark.R
Update connection_spark.R

Windows Spark logs location moved to subdirectory logs/log4j.spark.log.
rstudio/sparklyr,kevinykuo/sparklyr,kevinykuo/sparklyr,kevinykuo/sparklyr,rstudio/sparklyr,rstudio/sparklyr,kevinykuo/sparklyr,rstudio/sparklyr