fix wrong src_id and dst_id in PagerankNaive.java

DummyToPageRankLinksMapper created the edge file which has three elements in every line.
You can see PagerankData.java: line 25, output.collect(key, new Text(from + delim + to)); 
The src_id and dst_id should be the second and third element in the value text line according to DummyToPageRankLinksMapper of PagerankData.java