Added primary school as a poi AddressType to silence SafeEnumAdapter …

[jdcohen220]

This is similar to #377 and #378. Added the primary school element to AddressType enums

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[jdcohen220]

@googlebot I signed it!

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[coveralls]

Coverage increased (+0.01%) to 74.012% when pulling 9f95ed9 on jdcohen220:master into 22a2b4c on googlemaps:master.