Ignore FindBugs bug on deprecated field we must keep for binary compatibility.
Ignore FindBugs bug on deprecated field we must keep for binary
compatibility.

org.apache.commons.vfs2.provider.webdav4.Webdav4FileProvider#AUTHENTICATOR_TYPES,
MS_MUTABLE_ARRAY.
apache/commons-vfs,ecki/commons-vfs,ecki/commons-vfs,apache/commons-vfs