Remove double slash in database path creation

Visible to the user in some error conditions.

debian/changelog

@@ -28,6 +28,8 @@ dpkg (1.15.4) UNRELEASED; urgency=low
     Thanks to Simon Richter <sjr@debian.org>.
   * When aborting due to file conflicts print the version of the conflicted
     package. Closes: #540019
+  * Remove double slash in database path visible to the user in some error
+    conditions.
 
   [ Raphael Hertzog ]
   * Replace install-info by a wrapper around GNU's install-info. The wrapper

src/processarc.c

@@ -793,7 +793,7 @@ void process_archive(const char *filename) {
   debug(dbg_general, "process_archive updating info directory");
   varbufreset(&infofnvb);
   varbufaddstr(&infofnvb,admindir);
-  varbufaddstr(&infofnvb,"/" INFODIR "/");
+  varbufaddstr(&infofnvb, "/" INFODIR);
   infodirlen= infofnvb.used;
   varbufaddc(&infofnvb,0);
   dsd= opendir(infofnvb.buf);