create_template_postgis should use -e shell parameter

[Mitar]

create_template_postgis scripts should use #!/bin/bash -e as hashbang so that the script fails if any of the commands fails. This is useful for automation (like Travis CI installation of PostGIS).

[Olivier Le Thanh Duong]

After looking into it I'm not sure if it's such a good idea, because the script don't clean after itself in case of failure.
For example if a user doesn't have postgis installed, the first time the script run it will create the database template_postgis then fail to install the postgis extension in it. Then the user install postgis but the script will directly fail in subsequents runs since template_postgis will already exists. So this isn't really user friendly.

[Claude Paroz]

Thanks for looking. Considering that this script is not used any more with Postgis 2, and the minor effect it has, I suggest to "won't fix" the issue.