Retire fetch--tool helper to contrib/examples

When git-fetch was builtin-ized, the previous script was moved to
contrib/examples.  Now, it is the sole remaining user for
'git fetch--tool'.

The fetch--tool code is still worth keeping around so people can
try out the old git-fetch.sh, for example when investigating
regressions from the builtinifaction.
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Makefile

@@ -601,7 +601,6 @@ BUILTIN_OBJS += builtin-diff-index.o
 BUILTIN_OBJS += builtin-diff-tree.o
 BUILTIN_OBJS += builtin-diff.o
 BUILTIN_OBJS += builtin-fast-export.o
-BUILTIN_OBJS += builtin-fetch--tool.o
 BUILTIN_OBJS += builtin-fetch-pack.o
 BUILTIN_OBJS += builtin-fetch.o
 BUILTIN_OBJS += builtin-fmt-merge-msg.o

builtin.h

@@ -48,7 +48,6 @@ extern int cmd_diff_tree(int argc, const char **argv, const char *prefix);
 extern int cmd_fast_export(int argc, const char **argv, const char *prefix);
 extern int cmd_fetch(int argc, const char **argv, const char *prefix);
 extern int cmd_fetch_pack(int argc, const char **argv, const char *prefix);
-extern int cmd_fetch__tool(int argc, const char **argv, const char *prefix);
 extern int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix);
 extern int cmd_for_each_ref(int argc, const char **argv, const char *prefix);
 extern int cmd_format_patch(int argc, const char **argv, const char *prefix);

git.c

@@ -304,7 +304,6 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "fast-export", cmd_fast_export, RUN_SETUP },
 		{ "fetch", cmd_fetch, RUN_SETUP },
 		{ "fetch-pack", cmd_fetch_pack, RUN_SETUP },
-		{ "fetch--tool", cmd_fetch__tool, RUN_SETUP },
 		{ "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 		{ "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 		{ "format-patch", cmd_format_patch, RUN_SETUP },