check-whitespace: avoid alerts about upstream commits

Every once in a while, whitespace errors are introduced in Git for
Windows' rebases to newer Git versions, simply by virtue of integrating
upstream commits that do not follow upstream Git's own whitespace rule.
In Git v2.50.0-rc0, for example, 03f2915541a4 (xdiff: disable
cleanup_records heuristic with --minimal, 2025-04-29) introduced a
trailing space.

Arguably, non-actionable alerts are worse than no alerts at all, so
let's suppress those alerts that we cannot do anything about, anyway.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

ci/check-whitespace.sh

@@ -19,6 +19,7 @@ problems=()
 commit=
 commitText=
 commitTextmd=
+committerEmail=
 goodParent=
 
 if ! git rev-parse --quiet --verify "${baseCommit}"
@@ -27,7 +28,7 @@ then
     exit 1
 fi
 
-while read dash sha etc
+while read dash email sha etc
 do
 	case "${dash}" in
 	"---") # Line contains commit information.
@@ -40,10 +41,14 @@ do
 		commit="${sha}"
 		commitText="${sha} ${etc}"
 		commitTextmd="[${sha}](${url}/commit/${sha}) ${etc}"
+		committerEmail="${email}"
 		;;
 	"")
 		;;
 	*) # Line contains whitespace error information for current commit.
+		# Quod licet Iovi non licet bovi
+		test gitster@pobox.com != "$committerEmail" || break
+
 		if test -n "${goodParent}"
 		then
 			problems+=("1) --- ${commitTextmd}")
@@ -64,7 +69,7 @@ do
 		echo "${dash} ${sha} ${etc}"
 		;;
 	esac
-done <<< "$(git log --check --pretty=format:"---% h% s" "${baseCommit}"..)"
+done <<< "$(git log --check --pretty=format:"---% ce% h% s" "${baseCommit}"..)"
 
 if test ${#problems[*]} -gt 0
 then