journald: enforce longer line length limit during "setup" phase of stream protocol

This PR made modification on Lennart Poettering's basis. Fix the LineMax's function failure problem.

Signed-off-by: Yangyang Shen <shenyangyang4@huawei.com>
(cherry picked from commit 80e97206)
(cherry picked from commit 9d5c5e4f)
(cherry picked from commit 655ba5aa)