[fzf-tmux] Ensure that the same $TERM value is used in split

Fix #305. ncurses can crash on invalid $TERM. fzf-tmux uses bash on
a new pane so we have to make sure that the $TERM is consistent with
that of the hosting shell.

bin/fzf-tmux

@@ -107,7 +107,7 @@ fail() {
 fzf="$(which fzf 2> /dev/null)" || fzf="$(dirname "$0")/fzf"
 [ -x "$fzf" ] || fail "fzf executable not found"
 
-envs="env "
+envs="env TERM=$TERM "
 [ -n "$FZF_DEFAULT_OPTS"    ] && envs="$envs FZF_DEFAULT_OPTS=$(printf %q "$FZF_DEFAULT_OPTS")"
 [ -n "$FZF_DEFAULT_COMMAND" ] && envs="$envs FZF_DEFAULT_COMMAND=$(printf %q "$FZF_DEFAULT_COMMAND")"