Tweak service for higher priority

Running as IO/CPU priority idle results in very starved git processes,
especially on busy systems. This causes repos to remain locked for too
long, so is not what we want. Drop IO scheduling setting and raise CPU
scheduling to "batch" from "idle".

Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
diff --git a/contrib/grok-fsck@.service b/contrib/grok-fsck@.service
index 659c24b..f6badad 100644
--- a/contrib/grok-fsck@.service
+++ b/contrib/grok-fsck@.service
@@ -8,8 +8,7 @@
 EnvironmentFile=-/etc/sysconfig/grokmirror.default
 EnvironmentFile=-/etc/sysconfig/grokmirror.%i
 ExecStart=/usr/bin/grok-fsck -c /etc/grokmirror/%i.conf ${EXTRA_FSCK_OPTS}
-IOSchedulingClass=idle
-CPUSchedulingPolicy=idle
+CPUSchedulingPolicy=batch
 # To override these users, create a drop-in systemd conf file in
 # /etc/systemd/system/grok-fsck@[foo].service.d/10-usergroup.conf:
 # [Service]