LockSet: encapsulate acquire() in try-except
LockSet: encapsulate acquire() in try-except

This patch adds a try/except area around most of the acquire() code (everything
after the intial condition checks). Since the except: clause contains just a
'raise' nothing really changes except the indentation of the code.

This is done in a separate commit to insulate and make clearer what the real
code changes done in the upcoming patch are.

Reviewed-by: imsnah



yiannist/ganeti,apyrgio/snf-ganeti,grnet/snf-ganeti,yiannist/ganeti,grnet/snf-ganeti,leshchevds/ganeti,ganeti/ganeti,onponomarev/ganeti,mbakke/ganeti,ganeti-github-testing/ganeti-test-1,ganeti/ganeti,andir/ganeti,dimara/ganeti,onponomarev/ganeti,leshchevds/ganeti,andir/ganeti,dimara/ganeti,bitemyapp/ganeti,apyrgio/ganeti,ganeti/ganeti,mbakke/ganeti,leshchevds/ganeti,mbakke/ganeti,apyrgio/ganeti,ganeti-github-testing/ganeti-test-1,apyrgio/snf-ganeti,andir/ganeti,yiannist/ganeti,bitemyapp/ganeti