Loads the latest package information from the channel server.
This method contacts the packages channel server using a PEAR_Remote instance. If any errors are encountered (channel server does not host the package, bad package name, etc.) they will be pushed onto the error stack.
Note: Since version 0.5.2, protocol REST 1.0 is also supported. So we try to contact the packages channel server using a PEAR_REST instance, if this channel support the protocol, rather than default protocol XMLRPC.
throws PEAR_PACKAGEUPDATE_ERROR_NOPACKAGE, if package name was set to empty.
throws PEAR_PACKAGEUPDATE_ERROR_NOCHANNEL, if channel was set to empty.
throws PEAR_PACKAGEUPDATE_ERROR_NOINFO, when there are no information available about the package name hosted on the channel server.