runtime: Fix firecracker config

The build was setting a `FCVALIDPATHS` variable for firecracker, but
that was never being used. Conversely, the firecracker configuration
template was expecting a `FCVALIDHYPERVISORPATHS`, but that variable was
never being set.

Resolve by only setting the `FCVALIDHYPERVISORPATHS` variable to ensure
the generated firecracker config is valid once again.

Fixes: #3005

From kata-containers/kata-containers#1002
Fixing kata-containers/kata-containers#1001

Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>
Signed-off-by: Christophe de Dinechin <dinechin@redhat.com>

Makefile

@@ -141,7 +141,7 @@ CLHPATH := $(CLHBINDIR)/$(CLHCMD)
 CLHVALIDHYPERVISORPATHS := [\"$(CLHBINDIR)/$(CLHCMD)\"]
 
 FCPATH = $(FCBINDIR)/$(FCCMD)
-FCVALIDPATHS = [\"$(FCPATH)\"]
+FCVALIDHYPERVISORPATHS = [\"$(FCPATH)\"]
 FCJAILERPATH = $(FCBINDIR)/$(FCJAILERCMD)
 FCVALIDJAILERPATHS = [\"$(FCJAILERPATH)\"]