AA: asterisk-chan-sccp-b: fix PKG_SOURCE_URL, URL, maintainer and dependency

This patch fixes asterisk-chan-sccp-b dependency that breaks asterisk18
menu in openwrt menuconfig, fixes SVN repo URL (HTTP 404 error), project
URL (also HTTP error 404) and removes package maintainer variable.

Signed-off-by: Jiri Slachta <slachta@cesnet.cz>

git-svn-id: svn://svn.openwrt.org/openwrt@36750 3c298f89-4303-0410-b956-a3cf2f4a3e73