correct the incomplete fix of r3003

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/matrix@3007 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
start using Memzero() instead of AZERO() {as in R`s source}

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/matrix@3008 edb9625f-4e0d-4859-8d74-9fd3b1da38cb