ciso_rpm_files (typo, should be cisco_rpm_files) is keep growing with duplicated items

[skwsk]

gisobuild_exr_engine.py

1. Typo : ciso_rpm_files should be cisco_rpm_files

2. ciso_rpm_files keep growing with duplicated items. The below lines do not need to execute multiple times, should be only once around line 527.

                                    for repo_path in repo_paths:
                                        cisco_rpm=("%s/%s*.rpm" %(repo_path, platform))
                                        ciso_rpm_files += glob.glob(cisco_rpm)

[cmohapat]

We will review and update asap.