dpkg: Set verify_output_rpm() as the default verify output formatter

The verify_output function pointer was not initialized, and if the user
did not specify --verify-output the program would segfault.

Reported-by: Raphaël Hertzog <hertzog@debian.org>

src/verify.c

@@ -48,8 +48,6 @@ struct verify_checks {
 
 typedef void verify_output_func(struct filenamenode *, struct verify_checks *);
 
-static verify_output_func *verify_output;
-
 static int
 verify_result_rpm(enum verify_result result, int check)
 {
@@ -82,6 +80,8 @@ verify_output_rpm(struct filenamenode *namenode, struct verify_checks *checks)
 	printf("%.9s %c %s\n", result, attr, namenode->name);
 }
 
+static verify_output_func *verify_output = verify_output_rpm;
+
 int
 verify_set_output(const char *name)
 {