devel/ccls: Fix distinfo after upstream retagged 0.20181225

• Add the commit currently tagged as 0.20181225 for future reference
• The old 0.20181225 tag was commit a9397cf6148d50b88a36ec2e90ea23813dda379d
• Drop upstreamed patch

Distfile diff:
https://people.freebsd.org/~tobik/logs/ccls-0.20181225-retag.diff