perssym.pat corrects symbols that lost their persistence after
being imported from a type patch made by an image with only
me970321.

It should be filed in by sysadmin after login, with no other 
metamodellers logged in. After the patch has successfully 
completed, you should log out, committing changes.

It does the following:
1) check we are logged in
2) open all projects
3) correct all non-persistent symbols
   - if we cannot obtain metamodelling lock, abandon and exit patch
4) announce success and say how many symbols were changed