Revert "libdpkg: Use varbuf_detach instead of ad-hoc code"

This reverts commit 77cae397a15baeca11c26aeb806b6be516e33d5f.

This change introdcued two points for memory leaks, which could be
significant, depending on the amount of calls to the functions.

debian/changelog

@@ -1,6 +1,6 @@
 dpkg (1.15.6.1) UNRELEASED; urgency=low
 
-  *
+  * Fix two memory leaks introduced in 1.15.6.
 
  -- Guillem Jover <guillem@debian.org>  Sat, 13 Mar 2010 05:23:34 +0100
 

lib/dpkg/dbmodify.c

@@ -384,6 +384,6 @@ const char *pkgadminfile(struct pkginfo *pkg, const char *whichfile) {
   varbufaddc(&vb,'.');
   varbufaddstr(&vb,whichfile);
   varbufaddc(&vb,0);
-  return varbuf_detach(&vb);
+  return vb.buf;
 }
 

lib/dpkg/fields.c

@@ -485,7 +485,7 @@ scan_word(const char **valp)
 
   *valp = p;
 
-  return varbuf_detach(&word);
+  return word.buf;
 }
 
 void