pw_env_setup: smarter checks for cipd auth

Only complain about not being logged into CIPD if we're actually
having trouble accessing things in CIPD.

Change-Id: I469aa0370572b1e596d99e691b21d6fa66a4f62e
diff --git a/bootstrap.sh b/bootstrap.sh
index 89e887b..c2b8028 100644
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -109,13 +109,18 @@
   fi
 fi
 
-. $SETUP_SH
+if [ -f $SETUP_SH ]; then
+  . $SETUP_SH
 
-if [ $_PW_IS_BOOTSTRAP -eq 0 ] && [ -z "$PW_ENVSETUP_QUIET" ]; then
-  echo
-  echo "To activate this environment in the future, run this in your terminal:"
-  echo
-  _pw_green "  . activate.sh\n"
+  if [ $_PW_IS_BOOTSTRAP -eq 0 ] && [ -z "$PW_ENVSETUP_QUIET" ]; then
+    echo
+    echo "To activate this environment in the future, run this in your "
+    echo "terminal:"
+    echo
+    _pw_green "  . activate.sh\n"
+  fi
+else
+  _pw_red "Error during bootstrap--see messages above."
 fi
 
 unset _PW_IS_BOOTSTRAP