Fix mongoose certs

The certificates used for MIM were broken by #4631. Erlang verifies `serverAuth` against `keyUsage`,
which causes the `ssl_certificate:verify_extkeyusage/2` function to fail.

The issue wasn't noticed immediately because the certificates are cached using a key generated by
`tools/make-certs-cache-key.sh`

Author: Kamil Wąż

tools/make-certs-cache-key.sh

@@ -6,7 +6,7 @@ year=$(date "+%Y")
 makefile_sum=$(sha1sum tools/ssl/Makefile | cut -d " " -f1)
 
 # Change it once incompatible changes are made in tools/ssl/ directory
-CERT_KEY_VERSION=1
+CERT_KEY_VERSION=2
 
 # CI_CERT_KEY_VERSION could be set in
 # https://app.circleci.com/settings/project/github/esl/MongooseIM/environment-variables

tools/ssl/openssl-mongooseim.cnf

@@ -22,7 +22,6 @@ commonName                  = MongooseIM
 subjectKeyIdentifier        = hash
 basicConstraints            = CA:FALSE
 keyUsage                    = digitalSignature, keyEncipherment
-extendedKeyUsage            = serverAuth
 subjectAltName              = @alternate_names
 nsComment                   = "Fake Dev-Only Certificate"