site.sh-configurable KVM rollbacks

@@ -31,12 +31,12 @@
 PROG=illumos-kvm
 # This is pretty meaningless, and should be "0.5.11" but we messed that up
 # by starting with "1.0.x" so this'll do.  There should be no need to change
 # this going forward.
 VER=1.0.5.11
-# Default to building tip, but if needed, specify the desired commit here
-COMMIT=
+# Default to building tip, but site.sh can force a specific commit checkout.
+COMMIT=$KVM_ROLLBACK
 SRC_REPO=https://github.com/joyent/illumos-kvm.git
 KERNEL_SOURCE=/code/omnios-$RELVER/illumos-omnios
 PROTO_AREA=$KERNEL_SOURCE/proto/root_i386
 PATCHDIR=patches.$PROG
 PKG=driver/virtualization/kvm

@@ -103,12 +103,12 @@
 make_package kvm.mog
 clean_up
 
 # Next, the utilities (they follow the kernel module version)
 PROG=illumos-kvm-cmd
-# Default to building tip, but if needed, specify the desired commit here
-COMMIT=
+# Default to building tip, but site.sh can force a specific commit checkout.
+COMMIT=$KVM_CMD_ROLLBACK
 SRC_REPO=https://github.com/joyent/illumos-kvm-cmd.git
 KERNEL_SOURCE=/code/omnios-$RELVER/illumos-omnios
 KVM_DIR=$TMPDIR/illumos-kvm-$VER
 PATCHDIR=patches.$PROG
 PKG=system/kvm