Description of problem:
I received ISE 500 when I tried to create repository with existing (duplicate) label or url. It is regression - on Satellite 5.7 it works correct.

Same problem on spacewalk: https://bugzilla.redhat.com/show_bug.cgi?id=1368490

Version-Release number of selected component (if applicable):
spacewalk-java-2.5.14-22.el6sat.noarch

How reproducible:
always

Steps to Reproduce:
1. go to: "Channels" --> "Manage Software Channels" --> "Create Repository"
2. create a repository with same URL or label.
3. receive Internal Server Error 

Actual results:
Internal Server Error (500)

Expected results:
without ISE 500 and show correct page

Additional info:
tail /var/log/tomcat6/catalina.out
ERROR com.redhat.rhn.frontend.servlets.SessionFilter - Error during transaction. Rolling back
javax.servlet.ServletException: javax.servlet.jsp.JspException: Cannot find bean under name contenttypes
	at org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:862)
	at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:791)
	at org.apache.jsp.WEB_002dINF.pages.channel.manage.repo.repodetails_jsp._jspService(Unknown Source
...
javax.servlet.jsp.JspException: Cannot find bean under name contenttypes
	at org.apache.struts.taglib.html.OptionsTag.getIterator(OptionsTag.java:377)
	at org.apache.struts.taglib.html.OptionsTag.doEndTag(OptionsTag.java:188)
	at org.apache.jsp.WEB_002dINF.pages.channel.manage.repo.repodetails_jsp._jspx_meth_html_005foptions_005f0(Unknown Source)
	at org.apache.jsp.WEB_002dINF.pages.channel.manage.repo.repodetails_jsp._jspx_meth_html_005fselect_005f0(Unknown Source)
	at org.apache.jsp.WEB_002dINF.pages.channel.manage.repo.repodetails_jsp._jspx_meth_html_005fform_005f0(Unknown Source)
	at org.apache.jsp.WEB_002dINF.pages.channel.manage.repo.repodetails_jsp._jspx_meth_html_005fhtml_005f0(Unknown Source)
	... 51 more