[SPARK-4421] Wrong link in spark-standalone.html

Modified the link of building Spark. (backport version of #3279.)

Author: Masayoshi TSUZUKI <tsudukim@oss.nttdata.co.jp>

Closes #3280 from tsudukim/feature/SPARK-4421-2 and squashes the following commits:

3b4d38d [Masayoshi TSUZUKI] [SPARK-4421] Wrong link in spark-standalone.html