Avoid races (and AV as result) when two attachments starts to use temporary page space simultaneously. 

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59887 65644016-39b1-43b1-bf79-96bc8fe82c15
Misc

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59888 65644016-39b1-43b1-bf79-96bc8fe82c15
Correction

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59889 65644016-39b1-43b1-bf79-96bc8fe82c15
Correction

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59890 65644016-39b1-43b1-bf79-96bc8fe82c15