Small bugfix

This fixes:

Starting capec
Traceback (most recent call last):
  File "/home/laurens/Source/cve-search/sbin/db_mgmt_capec.py", line 172, in <module>
    i = dbLayer.getLastModified('capec')
NameError: name 'dbLayer' is not defined
capec has 463 elements (0 update)

When doing '''python3 ./db_updater.py -c -i -v'''