Customer name in order is saved with two spaces if it has no middle name

[JerryBra]

Copied from Magento Bug Tracker

Steps to reproduce:
place an order without middle name

More technical details: https://magento.stackexchange.com/questions/80196/magento-1-9-2-0-table-sales-flat-order-grid-contains-extra-space-in-customer/80201?noredirect=1#answer-80201

Expected Result:
customer name is saved as "firstname lastname" (one space)

Actual Result:
customer name is saved as "firstname lastname" (two spaces) and can only be searched in the grid with both spaces

[JerryBra]

Solved in #31 but does not apply to existing orders. Install script needed to fix existing orders.