fix calling style of FileFd (no functional change)

apt-pkg/deb/debindexfile.cc

@@ -161,7 +161,7 @@ unsigned long debSourcesIndex::Size() const
    /* we need to ignore errors here; if the lists are absent, just return 0 */
    _error->PushToStack();
 
-   FileFd f = FileFd (IndexFile("Sources"), FileFd::ReadOnly, FileFd::Extension);
+   FileFd f(IndexFile("Sources"), FileFd::ReadOnly, FileFd::Extension);
    if (!f.Failed())
       size = f.Size();
 
@@ -290,7 +290,7 @@ unsigned long debPackagesIndex::Size() const
    /* we need to ignore errors here; if the lists are absent, just return 0 */
    _error->PushToStack();
 
-   FileFd f = FileFd (IndexFile("Packages"), FileFd::ReadOnly, FileFd::Extension);
+   FileFd f(IndexFile("Packages"), FileFd::ReadOnly, FileFd::Extension);
    if (!f.Failed())
       size = f.Size();
 
@@ -488,7 +488,7 @@ unsigned long debTranslationsIndex::Size() const
    /* we need to ignore errors here; if the lists are absent, just return 0 */
    _error->PushToStack();
 
-   FileFd f = FileFd (IndexFile(Language), FileFd::ReadOnly, FileFd::Extension);
+   FileFd f(IndexFile(Language), FileFd::ReadOnly, FileFd::Extension);
    if (!f.Failed())
       size = f.Size();