Add default CA bundle location for DragonFlyBSD

Signed-off-by: Eygene Ryabinkin <rea@codelabs.ru>

Changelog.rst

@@ -9,7 +9,7 @@ OfflineIMAP v6.5.6.1 (YYYY-MM-DD)
 =================================
 
 * Added default CA bundle location for OpenBSD
-  (GitHub pull #120).
+  (GitHub pull #120) and DragonFlyBSD.
 
 * Added OpenSSL exception clause to our main GPL to allow
   people to link with OpenSSL in run-time.  It is needed

offlineimap/utils/distro.py

@@ -15,7 +15,7 @@ __DEF_OS_LOCATIONS = {
     'freebsd': '/usr/local/share/certs/ca-root-nss.crt',
     'openbsd': '/etc/ssl/cert.pem',
     'netbsd': None,
-    'dragonfly': None,
+    'dragonfly': '/etc/ssl/cert.pem',
     'darwin': [
       # MacPorts, port curl-ca-bundle
       '/opt/local/share/curl/curl-ca-bundle.crt',