Add pipefail option in helpers common.sh library

This is needed because common.sh contains functions that use pipes,
and the script should fail if any command fails.

snf-image-helper/common.sh

@@ -167,5 +167,5 @@ check_if_excluded() {
 }
 
 trap cleanup EXIT
-
+set -o pipefail
 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :

snf-image-helper/snf-image-helper.in

@@ -20,7 +20,6 @@
 . @commondir@/common.sh
 
 set -e
-set -o pipefail
 
 if [ "x$1" != "x--force" ]; then
     echo "WARNING: Exiting, this command would cause the system to halt." >&2

snf-image-helper/tasks/50EnforcePersonality.in

@@ -25,7 +25,6 @@
 ### END TASK INFO
 
 set -e
-set -o pipefail
 
 . "@commondir@/common.sh"