Older mount.cifs programs passed this on to the kernel after parsing
the file. Make sure the kernel ignores that option.
Should fix:
    https://bugzilla.kernel.org/show_bug.cgi?id=43195
Cc: Sachin Prabhu <sprabhu@redhat.com>
Reported-by: Ronald <ronald645@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
 
        { Opt_ignore, "cred" },
        { Opt_ignore, "credentials" },
+       { Opt_ignore, "cred=%s" },
+       { Opt_ignore, "credentials=%s" },
        { Opt_ignore, "guest" },
        { Opt_ignore, "rw" },
        { Opt_ignore, "ro" },