reconstruct should not destroy a readable cyrus.expunge.

[Paul Turgyan]

I'm looking at the code for reconstruct,  and it seems weird to me  
that reconstruct,
after verifying a "good" cyrus.expunge file,  that it deletes all the  
referenced mail
files and then deletes the cyrus.expunge file.

If the cyrus.expunge file can be read,  shouldn't we just verify that  
all the referenced
message files are readable,  and then leave cyrus.expunge alone?    
Maybe if there
are referenced  message files missing or unreadable,  we could  
rewrite the
cyrus.expunge file removing the missing files.

paul turgyan