Generated SSL certificate files should only be readable by owner.

[srbaker]

Before

$ bin/neo4j console
WARNING: Max 1024 open files allowed, minimum of 40 000 recommended. See the Neo4j manual.
Starting Neo4j Server console-mode...
2016-12-13 14:39:03.450+0100 INFO  No SSL certificate found, generating a self-signed certificate..
2016-12-13 14:39:07.268+0100 INFO  Successfully started database
2016-12-13 14:39:07.299+0100 INFO  Starting HTTP on port 7474 (4 threads available)
2016-12-13 14:39:07.497+0100 INFO  Enabling HTTPS on port 7473
2016-12-13 14:39:07.569+0100 INFO  Mounting static content at /webadmin
2016-12-13 14:39:07.621+0100 INFO  Mounting static content at /browser
2016-12-13 14:39:08.598+0100 INFO  Remote interface ready and available at http://localhost:7474/
^C2016-12-13 14:39:28.383+0100 INFO  Neo4j Server shutdown initiated by request
2016-12-13 14:39:28.393+0100 INFO  Successfully shutdown Neo4j Server
2016-12-13 14:39:28.505+0100 INFO  Successfully stopped database
2016-12-13 14:39:28.505+0100 INFO  Successfully shutdown database
$ ls -l conf/ssl
total 8
-rw-r--r-- 1 srbaker srbaker 631 Dec 13 14:39 snakeoil.cert
-rw-r--r-- 1 srbaker srbaker 912 Dec 13 14:39 snakeoil.key

After

$ bin/neo4j console
WARNING: Max 1024 open files allowed, minimum of 40 000 recommended. See the Neo4j manual.
Starting Neo4j Server console-mode...
2016-12-13 14:47:02.547+0100 INFO  No SSL certificate found, generating a self-signed certificate..
2016-12-13 14:47:06.039+0100 INFO  Successfully started database
2016-12-13 14:47:06.063+0100 INFO  Starting HTTP on port 7474 (4 threads available)
2016-12-13 14:47:06.269+0100 INFO  Enabling HTTPS on port 7473
2016-12-13 14:47:06.327+0100 INFO  Mounting static content at /webadmin
2016-12-13 14:47:06.371+0100 INFO  Mounting static content at /browser
2016-12-13 14:47:07.399+0100 INFO  Remote interface ready and available at http://localhost:7474/
^C2016-12-13 14:47:13.193+0100 INFO  Neo4j Server shutdown initiated by request
2016-12-13 14:47:13.204+0100 INFO  Successfully shutdown Neo4j Server
2016-12-13 14:47:13.452+0100 INFO  Successfully stopped database
2016-12-13 14:47:13.452+0100 INFO  Successfully shutdown database
$ ls -l conf/ssl/
total 8
-rw------- 1 srbaker srbaker 631 Dec 13 14:47 snakeoil.cert
-rw------- 1 srbaker srbaker 916 Dec 13 14:47 snakeoil.key

changelog [security]

[spacecowboy]

Nice

[spacecowboy]

Test failure is unrelated to this PR and seems to be something flaky at that.