live: partprobe breaks with mounted partitions

partprobe requires that all disk partitions are unmounted.

partprobe needs to be called to report the OS that the partition table
has changed, otherwise ogclient reports incorrect partition information.

iterate over the partition list and mount cache after partprobe is
called.

src/live/ogOperations.py

@@ -346,7 +346,6 @@ class OgLiveOperations:
             cxt.add_partition(pa)
 
         cxt.write_disklabel()
-        subprocess.run(['partprobe', f'/dev/{diskname}'])
 
         for part in partlist:
             if part["filesystem"] == 'EMPTY':
@@ -358,10 +357,20 @@ class OgLiveOperations:
             partition = int(part["partition"])
             if fs == 'cache':
                 mkfs('ext4', int(disk), partition, label='CACHE')
-                init_cache()
             else:
                 mkfs(fs, int(disk), partition)
 
+        ret = subprocess.run(['partprobe', f'/dev/{diskname}'])
+        logging.info(f'partprobe /dev/{diskname} reports {ret.returncode}')
+
+        for part in partlist:
+            if part["filesystem"] == 'EMPTY':
+                continue
+
+            fs = part["filesystem"].lower()
+            if fs == 'cache':
+                init_cache()
+
         logging.info('Partition setup command OK')
         result = self.refresh(ogRest)