balg02: Make minor adjusting to allow for testing

* .guix/guix-na/config/balg02.scm (guix-na): Add function balg02 which parameterized the disk
that the bootloader (grub) is installed to. This enables testing in a vm where the disk may
not match what is used on the physical server.

.guix/guix-na/config/balg02.scm

@@ -27,11 +27,11 @@
   #:use-module (gnu services networking)
   #:use-module (gnu services ssh)
   #:use-module (gnu services web)
-  #:export (%system))
+  #:export (balg02 %system))
 
 (define %automation-user "auto")
 
-(define %system
+(define (balg02 disk)
   (operating-system
    (host-name "balg02")
    (timezone "US/Central")
@@ -44,7 +44,7 @@
                 (terminal-outputs '(console serial_1))
                 (serial-unit 1)
                 (serial-speed 115200)
-                (targets '("/dev/sda"))))
+                (targets `(,disk))))
 
    (file-systems (append
                   (list (file-system
@@ -117,3 +117,5 @@
                       (name-servers '("216.37.64.2" "216.37.64.3")))))
       (service ntp-service-type))
      %base-services))))
+
+(define %system (balg02 "/dev/sda"))