No exit with error if don't find sudoers line

This way, actions can be done with the result (eg. add the line,…).

client/fix_backuppc_linux_sudo.sh

@@ -29,7 +29,6 @@ is_user() ## [[[
 	fi
 }
 ## ]]]
-
 is_sudoers_line() ## [[[
 {
 	line_to_check="${1}"
@@ -39,8 +38,8 @@ is_sudoers_line() ## [[[
 		[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : ${line_to_check} line is available in sudo configuration."
 		return "${SUCCESS}"
 	else
-		printf '\e[1;31m%-6s\e[m\n' "ERROR : ${line_to_check} was not found in sudo configuration."
-		exit "${ERROR}"
+		[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : ${line_to_check} was not found in sudo configuration."
+		return "${ERROR}"
 	fi
 }
 ## ]]]