Invoices: Custom logo not included in PDF

[dd32]

Currently if a custom logo is set for the invoice, it's not included in the generated PDF.

In testing locally, I'm unable to duplicate it, other than to observe that the default logo works and is pulled in as a /absolute/path/to/file.png where as custom logos are https://wordcamp.site/path/to/file.png.

The attached patch attempts to use absolute path to the image in the hope that's the problem, invoice generation works before and after for my test environment.

[vedjain]

Commited in r8798