kola: Fix path for qemu-bios argument

After changing the qemu working directory, relative qemu-bios path
arguments stopped working.
Handle relative paths by prepending kola's current working directory.
The changes from
git diff --no-index platform/machine/qemu/ platform/machine/unprivqemu/
show that only platform-specific options differ. As a test
cl.tpm.root-cryptenroll passed for --platform=qemu and
--platform=qemu-unpriv when run with
--qemu-bios=flatcar_production_qemu_uefi_efi_code.fd as relative path
argument.

platform/machine/qemu/cluster.go

@@ -132,7 +132,15 @@ ExecStartPost=/usr/bin/ln -fs /run/metadata/flatcar /run/metadata/coreos
 
 	// This uses path arguments with path values being
 	// relative to the folder created for this machine
-	qmCmd, extraFiles, err := platform.CreateQEMUCommand(qc.flight.opts.Board, qm.id, qc.flight.opts.BIOSImage, qm.consolePath, confPath, qc.flight.diskImagePath, conf.IsIgnition(), options)
+	biosImage := qc.flight.opts.BIOSImage
+	if !strings.HasPrefix(biosImage, "/") {
+		cwd, err := os.Getwd()
+		if err != nil {
+			return nil, fmt.Errorf("getting cwd: %v", err)
+		}
+		biosImage = filepath.Join(cwd, biosImage)
+	}
+	qmCmd, extraFiles, err := platform.CreateQEMUCommand(qc.flight.opts.Board, qm.id, biosImage, qm.consolePath, confPath, qc.flight.diskImagePath, conf.IsIgnition(), options)
 	if err != nil {
 		return nil, err
 	}

platform/machine/unprivqemu/cluster.go

@@ -145,7 +145,15 @@ LinkLocalAddressing=no
 	}
 	// This uses path arguments with path values being
 	// relative to the folder created for this machine
-	qmCmd, extraFiles, err := platform.CreateQEMUCommand(qc.flight.opts.Board, qm.id, qc.flight.opts.BIOSImage, qm.consolePath, confPath, qc.flight.diskImagePath, conf.IsIgnition(), options)
+	biosImage := qc.flight.opts.BIOSImage
+	if !strings.HasPrefix(biosImage, "/") {
+		cwd, err := os.Getwd()
+		if err != nil {
+			return nil, fmt.Errorf("getting cwd: %v", err)
+		}
+		biosImage = filepath.Join(cwd, biosImage)
+	}
+	qmCmd, extraFiles, err := platform.CreateQEMUCommand(qc.flight.opts.Board, qm.id, biosImage, qm.consolePath, confPath, qc.flight.diskImagePath, conf.IsIgnition(), options)
 	if err != nil {
 		return nil, err
 	}