[libdmapsharing] Fix clang warning

[W. Michael Petullo <wmpetullo src gnome org>]

commit 28d26ba51dac6565a796a4e2c68ad28f89af398f
Author: Bastien Nocera <hadess hadess net>
Date:   Tue Oct 29 11:42:31 2013 +0100

    Fix clang warning
    
    dmap-md5.c:187:26: warning: 'memset' call operates on objects of type 'MD5_CTX'
    while the size is based on a different
          type 'MD5_CTX *' [-Wsizeof-pointer-memaccess]
            memset (ctx, 0, sizeof (ctx));  /* In case it's sensitive */
                    ~~~             ^~~
    
    That should be "sizeof(*ctx)" instead.
    
    See https://bugzilla.redhat.com/show_bug.cgi?id=1023528
    
    https://bugzilla.gnome.org/show_bug.cgi?id=711063

 libdmapsharing/dmap-md5.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libdmapsharing/dmap-md5.c b/libdmapsharing/dmap-md5.c
index 4472472..c646d6c 100644
--- a/libdmapsharing/dmap-md5.c
+++ b/libdmapsharing/dmap-md5.c
@@ -176,7 +176,7 @@ DMAP_MD5Final (DMAPHashContext * ctx, unsigned char digest[16])
        MD5Transform (ctx->buf, (guint32 *) ctx->in, ctx->version);
        byteReverse ((unsigned char *) ctx->buf, 4);
        memcpy (digest, ctx->buf, 16);
-       memset (ctx, 0, sizeof (ctx));  /* In case it's sensitive */
+       memset (ctx, 0, sizeof (*ctx)); /* In case it's sensitive */
 
        return;
 }