Small fixes for SSH usage

- dropbear launches bash as /bin/sh, which needs $HOME/.profile
- emergency_shell launches bash as bash -i, which needs $HOME/.bashrc
- when zfsbootmenu is launched via SSH, override control_term to point
  to the SSH TTY, so that output is always sent to the right location
- restore a TERM= value, so that SSH connections have a proper env

90zfsbootmenu/module-setup.sh

@@ -308,13 +308,15 @@ EOF
 [ -f /lib/zfsbootmenu-lib.sh ] && source /lib/zfsbootmenu-lib.sh
 
 export PATH=/usr/sbin:/usr/bin:/sbin:/bin
+export TERM=linux
+export HOME=/root
 
 zdebug "sourced /etc/profile"
 
 EOF
 
-  # Setup a default environment for all login shells
-  cat << EOF >> "${initdir}/.bashrc"
+  # Setup a default environment for bash -i
+  cat << EOF >> "${initdir}/root/.bashrc"
 [ -f /etc/profile ] && source /etc/profile
 [ -f /lib/zfsbootmenu-completions.sh ] && source /lib/zfsbootmenu-completions.sh
 export PS1="\033[0;33mzfsbootmenu\033[0m \w > "
@@ -327,7 +329,10 @@ alias trace="ztrace"
 alias debug="ztrace"
 alias help="/libexec/zfsbootmenu-help -L recovery-shell"
 
-zdebug "sourced /.bashrc"
+zdebug "sourced /root/.bashrc"
 
 EOF
+
+  # symlink to .profile for /bin/sh - launched by dropbear
+  ln -s "/root/.bashrc" "${initdir}/root/.profile"
 }

90zfsbootmenu/zfsbootmenu-lib.sh

@@ -2402,7 +2402,7 @@ emergency_shell() {
   echo -n "Launching emergency shell: "
   echo -e "${message}\n"
 
-  # -i (interactive) mode will source /.bashrc
+  # -i (interactive) mode will source $HOME/.bashrc
   /bin/bash -i
 
   # shellcheck disable=SC2034

90zfsbootmenu/zfsbootmenu.sh

@@ -67,6 +67,10 @@ if [ -d /libexec/setup.d ]; then
   unset _hook
 fi
 
+# Override control_term if executing over SSH
+# shellcheck disable=SC2034
+[ -n "${SSH_TTY}" ] && control_term="${SSH_TTY}"
+
 # shellcheck disable=SC2016
 fuzzy_default_options=( "--ansi" "--no-clear"
   "--layout=reverse-list" "--inline-info" "--tac" "--color=16"