Merge branch 'maint'

* maint:
  git-am.txt: advertise 'git am --abort' instead of 'rm .git/rebase-apply'
  bisect: visualize with git-log if gitk is unavailable

Documentation/git-am.txt

@@ -173,9 +173,9 @@ aborts in the middle.  You can recover from this in one of two ways:
   the index file to bring it into a state that the patch should
   have produced.  Then run the command with the '--resolved' option.
 
-The command refuses to process new mailboxes while the `.git/rebase-apply`
-directory exists, so if you decide to start over from scratch,
-run `rm -f -r .git/rebase-apply` before running the command with mailbox
+The command refuses to process new mailboxes until the current
+operation is finished, so if you decide to start over from scratch,
+run `git am --abort` before running the command with mailbox
 names.
 
 Before any patches are applied, ORIG_HEAD is set to the tip of the

git-bisect.sh

@@ -288,10 +288,12 @@ bisect_visualize() {
 
 	if test $# = 0
 	then
-		case "${DISPLAY+set}${SESSIONNAME+set}${MSYSTEM+set}${SECURITYSESSIONID+set}" in
-		'')	set git log ;;
-		set*)	set gitk ;;
-		esac
+		if test -n "${DISPLAY+set}${SESSIONNAME+set}${MSYSTEM+set}${SECURITYSESSIONID+set}" &&
+		   type gitk >/dev/null 2>&1; then
+			set gitk
+		else
+			set git log
+		fi
 	else
 		case "$1" in
 		git*|tig) ;;