Fix the removal of the db files on pogo -d command

The latest version of pogo gives me an error when destroying the setup:

rdijksman@pogo:~/pogo$ sudo ./pogo -d
URELEASE 18.04 True
pogodir /home/rdijksman/pogo
INFO: Attempting destroy from shared object file.
Deleting host bridge1. 
Deleting host bridge3. 
Deleting host host2. 
Deleting host bridge2. 
Deleting host host1. 
Stopping  sniffer on pogo-bridge1 bridge
Stopping  sniffer on pogo-bridge0 bridge
rm: cannot remove 'devices': No such file or directory
rm: cannot remove 'switches': No such file or directory
rdijksman@pogo:~/pogo$ ls -l
total 108
-rw-rw-r-- 1 rdijksman rdijksman   392 Nov  8 17:07 ARNO-DEV-NOTES.txt
drwxrwxr-x 5 rdijksman rdijksman  4096 Nov  8 17:07 aux
-rwxrwxr-x 1 rdijksman rdijksman  1431 Nov 10 19:47 config.cfg
drwxrwxr-x 5 rdijksman rdijksman  4096 Nov  8 17:07 configurations
-rwxrwxr-x 1 rdijksman rdijksman  6189 Nov  8 17:07 create-base-container.sh
-rw-r--r-- 1 root      root      12288 Nov 15 12:39 devices.db
-rw-rw-r-- 1 rdijksman rdijksman 10365 Nov  8 17:07 Endpoint.py
-rw-rw-r-- 1 rdijksman rdijksman  1589 Nov 15 11:55 Interface.py
-rwxrwxr-x 1 rdijksman rdijksman   853 Nov  8 17:07 lxd-reset.sh
-rw-rw-r-- 1 rdijksman rdijksman  1512 Nov  8 17:07 Misc.py
-rwxrwxr-x 1 rdijksman rdijksman  9036 Nov 15 11:55 pogo
drwxrwxr-x 2 rdijksman rdijksman  4096 Nov 15 12:15 __pycache__
-rw-rw-r-- 1 rdijksman rdijksman  3329 Nov  8 17:07 README.md
-rw-rw-r-- 1 rdijksman rdijksman  8770 Nov 15 11:55 STP_Bridge.py
-rw-r--r-- 1 root      root      12288 Nov 15 12:39 switches.db
-rw-rw-r-- 1 rdijksman rdijksman  2958 Nov 15 11:55 Switch.py
rdijksman@pogo:~/pogo$ git branch
  master
* new-pogo