syz-manager: don't take mutex when serving static files
syz-manager: don't take mutex when serving static files

Crash log serving does not touch any manager state.

zoulasc/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,zoulasc/syzkaller,dotweiba/syzkaller,dotweiba/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,xairy/syzkaller,zoulasc/syzkaller,google/syzkaller,dotweiba/syzkaller,dotweiba/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,zoulasc/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller