Silence GCC warnings about possibly uninitialized blob values

In fact, the blob is always initialized when get_attr_blob() returns
KDUMP_OK, but the C compiler is not smart enough to know, but it is a bad
habit to ignore compiler warnings. An unnecessary NULL initialization is
definitely cheaper. ;-)

Signed-off-by: Petr Tesarik <[email protected]>

src/kdumpfile/util.c

@@ -1068,7 +1068,7 @@ derived_attr_revalidate(kdump_ctx_t *ctx, struct attr_data *attr,
 			const struct attr_template *tmpl)
 {
 	const struct derived_attr_def *def = attr_to_derived_def(attr);
-	kdump_blob_t *blob;
+	kdump_blob_t *blob = NULL;
 	kdump_status status;
 	void *ptr;
 
@@ -1122,7 +1122,7 @@ derived_attr_update(kdump_ctx_t *ctx, struct attr_data *attr,
 		    const struct attr_template *tmpl)
 {
 	const struct derived_attr_def *def = attr_to_derived_def(attr);
-	kdump_blob_t *blob;
+	kdump_blob_t *blob = NULL;
 	kdump_status status;
 	void *ptr;