Update function check_virt (#121)

Adjusted to recognize 'KVM' when 'sys_manu' contains 'QEMU'.
(Detection was failing on BuyVM.net's KVM VPS)

bench.sh

@@ -159,6 +159,8 @@ check_virt() {
         virt="KVM"
     elif [[ "${sys_product}" == *KVM* ]]; then
         virt="KVM"
+    elif [[ "${sys_manu}" == *QEMU* ]]; then
+        virt="KVM"
     elif [[ "${cname}" == *KVM* ]]; then
         virt="KVM"
     elif [[ "${cname}" == *QEMU* ]]; then