问题：
An error occurred while collecting items to be installed
session context was:(profile=DefaultProfile, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=).
Unable to read repository at http://activiti.org/designer/update/plugins/org.activiti.designer.libs_5.18.0.201508100929.jar.
SSL peer shut down incorrectly
解决：