Fix for oil rig construction after fix for fishing ground construction

[neroden]

So, since I usually play early-period game and never get to the oil rigs, I didn't realize until today that my fix to check that fishing grounds were linked by sea to fishing ports broke the construction of oil rigs, since the factories which oil rigs deliver to are typically not on the coast at all.  :sigh:

The "oil-rig-fix" branch fixes this.

[jamespetts]

So, since I usually play early-period game and never get to the oil rigs, I didn't realize until today that my fix to check that fishing grounds were linked by sea to fishing ports broke the construction of oil rigs, since the factories which oil rigs deliver to are typically not on the coast at all.  :sigh:

The "oil-rig-fix" branch fixes this.

Thank you for that - now incorporated.