Unify `-x' shell attribute in cartridge scripts

Turn off debugging level output:
- `set +x' by default
- `set -x' should be enabled explicitely for debugging purposes only

Bug 1168512 - https://bugzilla.redhat.com/show_bug.cgi?id=1168512
Merge pull request #5989 from VojtechVitek/bug_1168512

Merged by openshift-bot
Unify `-eu' shell attributes in cartridge scripts

Fail on errors:
- `set -e' by default
- `set +e' should be enabled explicitely for a certain sequence of
commands only

Fail on unset variables:
- `set -u' by default
- `set +u' should be enabled explicitely for a certain sequence of
commands only

https://bugzilla.redhat.com/show_bug.cgi?id=1168512