Description of problem:
When the URL contains a space on the beginning or end of the input field, spacewalk-repo-sync fails.


Version-Release number of selected component (if applicable):
5.4

How reproducible:
Always

Steps to Reproduce:
1. Go to https://rhn.example.com/rhn/channels/manage/repos/RepoCreate.do
2. Enter A repository URL such as " http://repo.exmple.com/repo/x86_64 " 
3. Fire up spacewalk-repo-sync -c example-cannel or schedule a sync in the webUI
  
Actual results:
Scheduled sync does not show any error in the log.
spacewalk-repo-sync -c example-channel result:

# spacewalk-repo-sync -c example-channel
Traceback (most recent call last):
  File "/usr/bin/spacewalk-repo-sync", line 72, in ?
    sys.exit(abs(main() or 0))
  File "/usr/bin/spacewalk-repo-sync", line 66, in main
    sync.main()
  File "/usr/share/rhn/satellite_tools/reposync.py", line 103, in main
    self.import_packages(plugin, url)
  File "/usr/share/rhn/satellite_tools/reposync.py", line 134, in import_packages
    packages = plug.list_packages()
  File "/usr/share/rhn/satellite_tools/repo_plugins/yum_src.py", line 57, in list_packages
    sack.populate(repo, 'metadata', None, 0)
  File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 168, in populate
    if self._check_db_version(repo, mydbtype):
  File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 226, in _check_db_version
    return repo._check_db_version(mdtype)
  File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1229, in _check_db_version
    repoXML = self.repoXML
  File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1402, in <lambda>
    repoXML = property(fget=lambda self: self._getRepoXML(),
  File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1398, in _getRepoXML
    raise Errors.RepoError, msg
yum.Errors.RepoError: Cannot retrieve repository metadata (repomd.xml) for repository: example-channel. Please verify its path and try again
#

Expected results:
The WebUI should filter out spaces and create an error on other invalid characters.


Additional info:
It also accepts semicolons, single quotes etc. Maybe it is also security related? (SQL-Injections)