spark git commit: [SPARK-15059][CORE] Remove fine-grained lock in ChildFirstURLClassLoader to avoid dead lock

Repository: spark Updated Branches: refs/heads/master 84b3a4a87 -> f5623b460 [SPARK-15059][CORE] Remove fine-grained lock in ChildFirstURLClassLoader to avoid dead lock ## What changes were proposed in this pull request? In some cases, fine-grained lock have race condition with class-loader

spark git commit: [SPARK-15059][CORE] Remove fine-grained lock in ChildFirstURLClassLoader to avoid dead lock

Repository: spark Updated Branches: refs/heads/branch-2.0 a08d2c954 -> 50adfcdce [SPARK-15059][CORE] Remove fine-grained lock in ChildFirstURLClassLoader to avoid dead lock ## What changes were proposed in this pull request? In some cases, fine-grained lock have race condition with class-loa