Cleanup conference join. (Issue #12)

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4180 43c1dc8c-776e-4df2-8ef1-6e829299be21
Fixed spelling mistake in function name

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4181 43c1dc8c-776e-4df2-8ef1-6e829299be21
Followed revision 4179

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4182 43c1dc8c-776e-4df2-8ef1-6e829299be21