Disable Backblaze B2 backups until #1899 is resolved

CHANGELOG.md

@@ -6,7 +6,6 @@ In Development
 
 * Incoming emails with SPF/DKIM/DMARC failures now have a higher spam score, and these messages are more likely to appear in the junk folder, since they are often spam/phishing.
 * A new Download button in the control panel's External DNS page can be used to download the required DNS records in zonefile format.
-* Backblaze B2 is now a supported backup protocol.
 * Fixed the problem when the control panel would report DNS entries as Not Set by increasing a bind query limit.
 * Fixed a control panel startup bug on some systems.
 * Fixed the MTA-STS policy file's line endings.

management/templates/system-backup.html

@@ -18,7 +18,6 @@
         <option value="local">{{hostname}}</option>
         <option value="rsync">rsync</option>
         <option value="s3">Amazon S3</option>
-        <option value="b2">Backblaze B2</option>
       </select>
     </div>
   </div>

setup/management.sh

@@ -27,10 +27,9 @@ done
 # provision free TLS certificates.
 apt_install duplicity python-pip virtualenv certbot
 
-# b2sdk is used for backblaze backups.
 # boto is used for amazon aws backups.
 # Both are installed outside the pipenv, so they can be used by duplicity
-hide_output pip3 install --upgrade b2sdk boto
+hide_output pip3 install --upgrade boto
 
 # Create a virtualenv for the installation of Python 3 packages
 # used by the management daemon.
@@ -51,7 +50,7 @@ hide_output $venv/bin/pip install --upgrade \
 	rtyaml "email_validator>=1.0.0" "exclusiveprocess" \
 	flask dnspython python-dateutil \
   qrcode[pil] pyotp \
-	"idna>=2.0.0" "cryptography==2.2.2" boto psutil postfix-mta-sts-resolver b2sdk
+	"idna>=2.0.0" "cryptography==2.2.2" boto psutil postfix-mta-sts-resolver
 
 # CONFIGURATION