installer: don't bail on errors in color setup

This is a hack to keep the installer working on systems without tput/terminfo.

tools/install.sh

-set -e
-
 # Use colors, but only if connected to a terminal, and that terminal
 # supports them.
 tput=$(which tput)
@@ -21,6 +19,11 @@ else
   BOLD=""
   NORMAL=""
 fi
+
+# Only enable exit-on-error after the non-critical colorization stuff,
+# which may fail on systems lacking tput or terminfo
+set -e
+
 CHECK_ZSH_INSTALLED=$(grep /zsh$ /etc/shells | wc -l)
 if [ ! $CHECK_ZSH_INSTALLED -ge 1 ]; then
   printf "${YELLOW}Zsh is not installed!${NORMAL} Please install zsh first!\n"