revert(3p/git): Revert merge of git upstream at v2.26.2

This causes cgit to serve error pages, which is undesirable.

This reverts commit 5229c9b232, reversing
changes made to f2b211131f.

third_party/git/git-submodule.sh

@@ -10,9 +10,8 @@ USAGE="[--quiet] [--cached]
    or: $dashless [--quiet] status [--cached] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] init [--] [<path>...]
    or: $dashless [--quiet] deinit [-f|--force] (--all| [--] <path>...)
-   or: $dashless [--quiet] update [--init] [--remote] [-N|--no-fetch] [-f|--force] [--checkout|--merge|--rebase] [--[no-]recommend-shallow] [--reference <repository>] [--recursive] [--[no-]single-branch] [--] [<path>...]
+   or: $dashless [--quiet] update [--init] [--remote] [-N|--no-fetch] [-f|--force] [--checkout|--merge|--rebase] [--[no-]recommend-shallow] [--reference <repository>] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] set-branch (--default|--branch <branch>) [--] <path>
-   or: $dashless [--quiet] set-url [--] <path> <newurl>
    or: $dashless [--quiet] summary [--cached|--files] [--summary-limit <n>] [commit] [--] [<path>...]
    or: $dashless [--quiet] foreach [--recursive] <command>
    or: $dashless [--quiet] sync [--recursive] [--] [<path>...]
@@ -37,7 +36,6 @@ reference=
 cached=
 recursive=
 init=
-require_init=
 files=
 remote=
 nofetch=
@@ -47,7 +45,6 @@ custom_name=
 depth=
 progress=
 dissociate=
-single_branch=
 
 die_if_unmatched ()
 {
@@ -242,15 +239,13 @@ cmd_add()
 	    die "$(eval_gettext "'\$sm_path' does not have a commit checked out")"
 	fi
 
-	if test -z "$force"
+	if test -z "$force" &&
+		! git add --dry-run --ignore-missing --no-warn-embedded-repo "$sm_path" > /dev/null 2>&1
 	then
-	    dryerr=$(git add --dry-run --ignore-missing --no-warn-embedded-repo "$sm_path" 2>&1 >/dev/null)
-	    res=$?
-	    if test $res -ne 0
-	    then
-		 echo >&2 "$dryerr"
-		 exit $res
-	    fi
+		eval_gettextln "The following path is ignored by one of your .gitignore files:
+\$sm_path
+Use -f if you really want to add it." >&2
+		exit 1
 	fi
 
 	if test -n "$custom_name"
@@ -471,10 +466,6 @@ cmd_update()
 		-i|--init)
 			init=1
 			;;
-		--require-init)
-			init=1
-			require_init=1
-			;;
 		--remote)
 			remote=1
 			;;
@@ -529,12 +520,6 @@ cmd_update()
 		--jobs=*)
 			jobs=$1
 			;;
-		--single-branch)
-			single_branch="--single-branch"
-			;;
-		--no-single-branch)
-			single_branch="--no-single-branch"
-			;;
 		--)
 			shift
 			break
@@ -563,8 +548,6 @@ cmd_update()
 		${reference:+"$reference"} \
 		${dissociate:+"--dissociate"} \
 		${depth:+--depth "$depth"} \
-		${require_init:+--require-init} \
-		$single_branch \
 		$recommend_shallow \
 		$jobs \
 		-- \
@@ -777,55 +760,6 @@ cmd_set_branch() {
 	fi
 }
 
-#
-# Configures a submodule's remote url
-#
-# $@ = requested path, requested url
-#
-cmd_set_url() {
-	while test $# -ne 0
-	do
-		case "$1" in
-		-q|--quiet)
-			GIT_QUIET=1
-			;;
-		--)
-			shift
-			break
-			;;
-		-*)
-			usage
-			;;
-		*)
-			break
-			;;
-		esac
-		shift
-	done
-
-	if test $# -ne 2
-	then
-		usage
-	fi
-
-	# we can't use `git submodule--helper name` here because internally, it
-	# hashes the path so a trailing slash could lead to an unintentional no match
-	name="$(git submodule--helper list "$1" | cut -f2)"
-	if test -z "$name"
-	then
-		exit 1
-	fi
-
-	url="$2"
-	if test -z "$url"
-	then
-		exit 1
-	fi
-
-	git submodule--helper config submodule."$name".url "$url"
-	git submodule--helper sync ${GIT_QUIET:+--quiet} "$name"
-}
-
 #
 # Show commit summary for submodules in index or working tree
 #
@@ -1125,7 +1059,7 @@ cmd_absorbgitdirs()
 while test $# != 0 && test -z "$command"
 do
 	case "$1" in
-	add | foreach | init | deinit | update | set-branch | set-url | status | summary | sync | absorbgitdirs)
+	add | foreach | init | deinit | update | set-branch | status | summary | sync | absorbgitdirs)
 		command=$1
 		;;
 	-q|--quiet)