* [JENKINS-37332] - Improve diagnostics of non-closed streams during reading of the manifests in PluginManager
* [JENKINS-37332] - Leakless processing of JarUrlConnection during Manifest parsing
* [JENKINS-37332] - Also implement leak-safe method for retrieving file modification date
* [JENKINS-37332] - Add spotcheck methods for manifest file access + Javadoc
* [JENKINS-37332] - Also test multi-line and empty attributes in the test
Although the plugiun manager was vulnerable getting information
out of Jenkins was harder - however it would still be possible to
do bad things such as reading from /dev/zero on Linux