copy-to-tmp 1 breaks sharing

[thommey]

with the new copy-to-tmp setting/code, it seems like copy-to-tmp being 1 breaks sharing under some circumstances (only observed with ssl so far).
there seems to be garbage memory before the actual userfile (45,000 bytes in one instance).
client stores the userfile but fails on loading it (no sanity check apparently), suggesting scripts/weed conversion and dies.

Found by: OUTsider (helped track down the issue)