出错：
PyrusInstallerException: Installation failed
PyrusAtomicFileTransactionMultiException: Unable to begin transaction
InvalidArgumentException: The given path must be a directory.
PyrusAtomicFileTransactionRuntimeException: Cannot rollback - not in a transaction
原因：首次运行时，目录设置错误，应该为php/lib
解决方案：
vi ~/.pear/pearconfig.xml
