Fix some issues:
1. Method DownloadUrl calls install_package, which is defined in SETUP-INSTALL-PACKAGES.py
2. On Oracle 6.4, when installing an RPM package, e.g.iperf-2.0.4-1.fc5.rf.x86_64.rpm, the output message is like "iperf   ##############"
Merge pull request #34 from lizzha/dev

Fix some issues: