add support for variable namespace alias for SREG attributes - fixes …

[CybotTM]

…SREG attributes not extracted if SREG namespace attribute name is not "openid_ns_sreg"

Support SREG attributes if namespace attribute name is NOT "openid_ns_sreg" by replacing hard coded SREG namespace attribute name with SREG namespace detection (see getAxAttributes()).

Makes working:

openid_ns_ext1=http://openid.net/extensions/sreg/1.1 openid_ext1_nickname=sebastian.mendel