TT#42869 Remove kernel.sysrq check from system-tests

kernel.sysr=1 was set for Vagrant VMs only and missing
on the real hardware AND for old releases, also it is
going to be removed from installer as well, since it
was committed to debug Proxmox issues only (review pending).

No need to test it here. Also it will fix system-tests
for upgrade 2.8->...->mr6.5 which is currently failing:
> KernelParam: kernel.sysrq: value: doesn't match, expect: ["1"] found: ["438"]
(it happens as kernel.sysrq was not set for old releases).

Change-Id: Id3b449ab9a8b48df4404233c418263029e289359

templates/610_kernel-sysctl-params.yaml.tt2

@@ -13,9 +13,6 @@ kernel-param:
   fs.suid_dumpable:
     value: "2"
 
-  kernel.sysrq:
-    value: "1"
-
   net.core.somaxconn:
     value: "512"