Merge changes I12e70a65,Ibccec851 into stable-2.16

* changes:
  Revert "Insert Change-Id at start of trailers"
  Revert "commit-msg: Remove obsolete comments"

resources/com/google/gerrit/server/commit-msg_test.sh

@@ -63,9 +63,9 @@ index 625fd613d9..03aeba3b21 100755
 @@ -38,6 +38,7 @@
  context
  line
-
+ 
 +hello, world
-
+ 
  context
  line
 EOF
@@ -111,7 +111,7 @@ EOF
 }
 
 # Change-Id goes after existing trailers.
-function test_at_start {
+function test_at_end {
   cat << EOF > input
 bla bla
 
@@ -119,16 +119,16 @@ Bug: #123
 EOF
 
   ${hook} input || fail "failed hook execution"
-  result=$(git interpret-trailers --parse input | head -1 | grep ^Change-Id)
+  result=$(tail -1 input | grep ^Change-Id)
   if [[ -z "${result}" ]] ; then
     echo "after: "
     cat input
 
-    fail "did not find Change-Id at start"
+    fail "did not find Change-Id at end"
   fi
 }
 
-function test_dash_at_start {
+function test_dash_at_end {
   if [[ ! -x /bin/dash ]] ; then
     echo "/bin/dash not installed; skipping dash test."
     return
@@ -142,12 +142,12 @@ EOF
 
   /bin/dash ${hook} input || fail "failed hook execution"
 
-  result=$(git interpret-trailers --parse input | head -1 | grep ^Change-Id)
+  result=$(tail -1 input | grep ^Change-Id)
   if [[ -z "${result}" ]] ; then
     echo "after: "
     cat input
 
-    fail "did not find Change-Id at start"
+    fail "did not find Change-Id at end"
   fi
 }
 

resources/com/google/gerrit/server/tools/root/hooks/commit-msg

@@ -48,7 +48,9 @@ if test ! -s "${dest}" ; then
   exit 1
 fi
 
-if ! git -c trailer.ifexists=doNothing interpret-trailers --where start \
+# Avoid the --in-place option which only appeared in Git 2.8
+# Avoid the --if-exists option which only appeared in Git 2.15
+if ! git -c trailer.ifexists=doNothing interpret-trailers \
       --trailer "Change-Id: I${random}" < "$1" > "${dest}" ; then
   echo "cannot insert change-id line in $1"
   exit 1