Makefile: remove $(NO_CURL) from $(SCRIPT_DEFINES)

Stop including $(NO_CURL) in $(SCRIPT_DEFINES). The "@NO_CURL@"
replacement added in 6c5c62f340 (Print an error if cloning a http
repo and NO_CURL is set, 2006-02-15) has not been referenced by
anything in-tree since 49eb8d39c7 (Remove contrib/examples/*,
2018-03-25).

That commit removed the reference from contrib/examples/*, but this
@@NO_CURL@@ hasn't been used since git-pull.sh was the primary entry
point for "git pull".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -2253,7 +2253,7 @@ hook-list.h: generate-hooklist.sh Documentation/githooks.txt
 	$(QUIET_GEN)$(SHELL_PATH) ./generate-hooklist.sh >$@
 
 SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):\
-	$(localedir_SQ):$(NO_CURL):$(USE_GETTEXT_SCHEME):$(SANE_TOOL_PATH_SQ):\
+	$(localedir_SQ):$(USE_GETTEXT_SCHEME):$(SANE_TOOL_PATH_SQ):\
 	$(gitwebdir_SQ):$(PERL_PATH_SQ):$(SANE_TEXT_GREP):$(PAGER_ENV):\
 	$(perllibdir_SQ)
 GIT-SCRIPT-DEFINES: FORCE
@@ -2268,7 +2268,6 @@ sed -e '1s|#!.*/sh|#!$(SHELL_PATH_SQ)|' \
     -e 's|@SHELL_PATH@|$(SHELL_PATH_SQ)|' \
     -e 's|@@DIFF@@|$(DIFF_SQ)|' \
     -e 's|@@LOCALEDIR@@|$(localedir_SQ)|g' \
-    -e 's/@@NO_CURL@@/$(NO_CURL)/g' \
     -e 's/@@USE_GETTEXT_SCHEME@@/$(USE_GETTEXT_SCHEME)/g' \
     -e $(BROKEN_PATH_FIX) \
     -e 's|@@GITWEBDIR@@|$(gitwebdir_SQ)|g' \