revert r7749 due to mistake in commit comment

git-svn-id: svn://svn.code.sf.net/p/freeorion/code/trunk@7750 dbd5520b-6a0a-0410-a553-f54834df5b05
bugfix for AI invasion problem introduced in r7748

git-svn-id: svn://svn.code.sf.net/p/freeorion/code/trunk@7751 dbd5520b-6a0a-0410-a553-f54834df5b05