Merge branch 'terencehill/decals_fix' into 'master'

Fix 2 decal issues

Closes #2128

See merge request xonotic/xonotic-data.pk3dir!1127

diff --cc qcsrc/common/effects/qc/damageeffects.qc
Simple merge

diff --cc qcsrc/common/mutators/mutator/overkill/okhmg.qc
Simple merge

diff --cc qcsrc/common/mutators/mutator/overkill/okmachinegun.qc
Simple merge

diff --cc qcsrc/common/mutators/mutator/overkill/oknex.qc
Simple merge

diff --cc qcsrc/common/mutators/mutator/overkill/okrpc.qc
Simple merge

diff --cc qcsrc/common/weapons/weapon/blaster.qc
Simple merge

diff --cc qcsrc/common/weapons/weapon/minelayer.qc
Simple merge

diff --cc qcsrc/common/weapons/weapon/vaporizer.qc
Simple merge

diff --cc qcsrc/server/damage.qc
Simple merge

diff --cc qcsrc/server/weapons/tracing.qc
Simple merge