Add missing quotes to echo statements

This didn't actually cause problems at runtime, but there was no reason
to keep the inconsistency, so I may as well fix it. Fixes issue #86.
Thanks to scott-feier for reporting.

install-setvars.sh

@@ -69,7 +69,7 @@ then
     if [ ! -d "$APPPATH" ]
     then
         echo "Failed to locate Big Sur recovery USB stick."
-        echo Remember to create it using createinstallmedia, and do not rename it.
+        echo "Remember to create it using createinstallmedia, and do not rename it."
         echo "If all else fails, try specifying the path to the USB stick"
         echo "as a command line parameter to this script."
         echo

micropatcher.sh

@@ -70,7 +70,7 @@ then
     if [ ! -d "$APPPATH" ]
     then
         echo "Failed to locate Big Sur recovery USB stick."
-        echo Remember to create it using createinstallmedia, and do not rename it.
+        echo "Remember to create it using createinstallmedia, and do not rename it."
         echo "If all else fails, try specifying the path to the USB stick"
         echo "as a command line parameter to this script."
         echo