If we're building an image and some package rebuilds while this is happening
some package can be removed/added to the ipk deploy directory. The image will
not depend on this package so we can safely ignore these cases rather than 
error out.

RP - 26/8/09

Index: opkg-utils/opkg-make-index
===================================================================
--- opkg-utils.orig/opkg-make-index	2009-08-26 17:21:26.000000000 +0100
+++ opkg-utils/opkg-make-index	2009-08-27 16:11:22.000000000 +0100
@@ -96,6 +96,7 @@
 files=glob(pkg_dir + '/*.ipk') + glob(pkg_dir + '/*.deb')
 files.sort()
 for filename in files:
+  try:
      basename = os.path.basename(filename)
      pkg = None
      fnameStat = os.stat(filename)
@@ -130,6 +131,12 @@
                to_morgue(basename)
           if opt_s:
                print filename
+  except OSError:
+      sys.stderr.write("Package %s disappeared on us!\n" % (filename))
+      continue
+  except IOError:
+      sys.stderr.write("Package %s disappeared on us!\n" % (filename))
+      continue
 
 pkgsStampsFile = open(stamplist_filename, "w")
 for f in pkgsStamps.keys():
@@ -148,6 +155,7 @@
 names = packages.packages.keys()
 names.sort()
 for name in names:
+  try:
      pkg = packages.packages[name]
      if locales_dir and pkg.depends:
          depends = string.split(pkg.depends, ',')
@@ -165,6 +173,13 @@
      if (verbose):
           sys.stderr.write("Writing info for package %s\n" % (pkg.package,))
      print pkg
+  except OSError:
+      sys.stderr.write("Package %s disappeared on us!\n" % (name))
+      continue
+  except IOError:
+      sys.stderr.write("Package %s disappeared on us!\n" % (name))
+      continue
+
 if packages_filename:
      sys.stdout.close()
      sys.stdout = old_stdout