Sync spelling of availabilityDate in XML to that of Schema
Sync spelling of availabilityDate in XML to that of Schema

The opacxml.xsd had the correct spelling of this member always.
The ASN.1 was mis-spelled and still is (API change) - we are
not changing this by this. However, the OPAC to XML conversion had yet
*another* typo. This is fixed by this commit.

dcrossleyau/yaz,dcrossleyau/yaz,nla/yaz,nla/yaz,nla/yaz,nla/yaz,dcrossleyau/yaz