HADOOP-18214. Update BUILDING.txt (#3811)

java-8-openjdk become openjdk-8-jdk (see both ubuntu and debian package's name)

Contributed by Giovambattista Vieri
Reviewed-by: Ayush Saxena <ayushsaxena@apache.org>

Change-Id: I63b2bbfdd575cf56d20cd6c8fff33a70cadda7f2
1 file changed