Fix several bugs

[NeKzor]

Highlights:

• 1ef78b4b41aef3c77717b0adc5716c5fc617bd43 Announcement did not go away because the cookie had no path.
• bbe4e311f6c6bece48c57257c77a9116e1d71e21 Fix invalid conditional statement since "" || null will always evaluate to null.

Upstreamed from fork: https://github.com/NeKzor/board