Faster loading of yaml logs
Faster loading of yaml logs

Skip as much lines as possible before loading the yaml structure. In fact,
skipping lines is way faster than loading yaml.

Change-Id: Iab760e51cd9e3b6e8dbc58401c41a56553a8175e

Linaro/lava-server,Linaro/lava-server,Linaro/lava-server,Linaro/lava-server