Grab input first, then obscure screen
Grab input first, then obscure screen

Rework lockscreen to grab the keyboard and pointer first and only obscure
the display if lockscreen successfully grabs both.

Change lockscreen not to retry if grabbing the input fails with an error
other than AlreadyGrabbed.

Change the retry interval to 100 milliseconds, and give up after 6 tries.

Based on upstream commits c2f975773d720e734dbdab9a1e9ae51b0972ae0c and
e378f735d857f7da124177e3540912d920be5022.

Miciah/slock-pam