tests/namespaces/tst7.xsl: fixed typo detected by new libxml2 code

* Minor cleanup of "typo" and some compilation warnings:
  tests/namespaces/tst7.xsl: fixed typo detected by new libxml2 code
  libxslt/keys.c, libxslt/xsltlocale.c, libexslt/date.c: trivial
  changes for gcc warnings.

svn path=/trunk/; revision=1489