Revert "allow the AI to base-walk without restrictions"

This reverts commit d08d3d6e238324c953c2d501514eb882e0e3e169.
fix #3569 , and possible many other bugs... if the place is not close to the base, instead of returning the error, continue to see if there is another place to build
Merge pull request #3570 from 0x7c00/bleed

Allow the AI to look for more space to build: fixes #3189