unixpwd: fix reentrance of unixpwd_setpwd() and unixpwd_setspw()#6729

semarie wants to merge 2 commits intoxapi-project:masterxapi-project/xen-api:masterfrom

semarie:unixpwd-reentrancesemarie/xen-api:unixpwd-reentranceCopy head branch name to clipboard