[MNG-5613] fix NullPointerException when error occur during project dependency graph creation
Submitted by: Sebastian Le Merdy <sebastian.lemerdy@gmail.com>
From: https://github.com/apache/maven/pull/13
MNG-4226: Detect JAVA_HOME on newer Mac OS X
Submitted by: Christopher Tubbs <ctubbsii@apache.org>
https://github.com/apache/maven/pull/11