Fix a typo in LogicalUnit.ExpandNames docstring
Fix a typo in LogicalUnit.ExpandNames docstring

s/locking.LEVEL_INSTANCES/locking.LEVEL_INSTANCE/

Reviewed-by: iustinp


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