cephconfig: escape un-escaped comment literals on write

in order to prevent configuration errors or the configuration being
misinterpreted.

Signed-off-by: Max Carrara <m.carrara@proxmox.com>
Tested-by: Friedrich Weber <f.weber@proxmox.com>

src/PVE/CephConfig.pm

@@ -105,6 +105,9 @@ sub write_ceph_config {
 	$cond_write_sec->($re);
     }
 
+    # Escape comment literals that aren't escaped already
+    $out =~ s/(?<!\\)([;#])/\\$1/gm;
+
     return $out;
 }