The link to "Specifying the Hadoop Version" currently points to http://spark.apache.org/docs/latest/building-with-maven.html#specifying-the-hadoop-version.

The correct link is: http://spark.apache.org/docs/latest/building-spark.html#specifying-the-hadoop-version

Author: Theodore Vasiloudis <tvas@sics.se>

Closes #4999 from thvasilo/patch-1 and squashes the following commits:

c34aea8 [Theodore Vasiloudis] Fix dead link in Readme