patch apt-pkg using mkostemp storing temporal file name

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index dca468c..394bc77 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -946,9 +946,6 @@ bool FileFd::Open(string FileName,unsigned int const Mode,APT::Configuration::Co
    if ((Mode & Atomic) == Atomic)
    {
       Flags |= Replace;
-      char *name = strdup((FileName + ".XXXXXX").c_str());
-      TemporaryFileName = string(mktemp(name));
-      free(name);
    }
    else if ((Mode & (Exclusive | Create)) == (Exclusive | Create))
    {
@@ -974,8 +971,20 @@ bool FileFd::Open(string FileName,unsigned int const Mode,APT::Configuration::Co
    else if_FLAGGED_SET(Atomic, O_EXCL);
    #undef if_FLAGGED_SET

-   if (TemporaryFileName.empty() == false)
-      iFd = open(TemporaryFileName.c_str(), fileflags, Perms);
+   if ((Mode & Atomic) == Atomic)
+   {
+      char *name = strdup((FileName + ".XXXXXX").c_str());
+
+      TemporaryFileName = string(name);
+
+      // The file is created with permissions 0600, that is,
+      // read plus write for owner only.
+      if((iFd = mkostemp(name, fileflags)) == -1)
+      {
+          return FileFdError("Could not create temporary file for %s", FileName.c_str());
+      }
+      free(name);
+   }
    else
       iFd = open(FileName.c_str(), fileflags, Perms);