Pass -f flag to curl, allowing 404s to return an error

git-svn-id: https://svn.macports.org/repository/macports/trunk/base@3109 d073be05-634f-4543-b044-5fe20cf6d1d6

src/port1.0/portfetch.tcl

@@ -59,7 +59,7 @@ default cvs.pre_args {"-d ${cvs.root}"}
 default fetch.cmd curl
 default fetch.dir {${distpath}}
 default fetch.args {"-o ${distfile}.TMP"}
-default fetch.pre_args ""
+default fetch.pre_args "-f"
 default fetch.post_args {"${site}/${distfile}"}
 
 default mirror_sites.listfile {"mirror_sites.tcl"}