Bug 1441718

This bug is created as a clone of upstream ticket:
https://pagure.io/freeipa/issue/6853

When trying to convert CA-less master to CA-full, the ipa-ca-install command fails with:

```console
# ipa-ca-install -p Secret123
Configuring certificate server (pki-tomcatd). Estimated time: 3 minutes
  [1/30]: creating certificate server user
  [2/30]: configuring certificate server instance
ipa.ipaserver.install.cainstance.CAInstance: CRITICAL Failed to configure CA instance: Command '/usr/sbin/pkispawn -s CA -f /tmp/tmpdVpOj5' returned non-zero exit status 1
ipa.ipaserver.install.cainstance.CAInstance: CRITICAL See the installation logs and the following files/directories for more information:
ipa.ipaserver.install.cainstance.CAInstance: CRITICAL   /var/log/pki/pki-tomcat
  [error] RuntimeError: CA configuration failed.

Your system may be partly configured.
Run /usr/sbin/ipa-server-install --uninstall to clean up.

CA configuration failed.
```

In the CA installation logs I can see this error:

```console
2017-04-07T14:00:17Z DEBUG stdout=Log file: /var/log/pki/pki-ca-spawn.20170407140017.log
Loading deployment configuration from /tmp/tmpdVpOj5.
Installing CA into /var/lib/pki/pki-tomcat.
Storing deployment configuration into /etc/sysconfig/pki/tomcat/pki-tomcat/ca/deployment.cfg.

Installation failed: Directory '/etc/pki/pki-tomcat' already exists!


2017-04-07T14:00:17Z DEBUG stderr=pkispawn    : ERROR    ....... Directory '/etc/pki/pki-tomcat' already exists!

2017-04-07T14:00:17Z CRITICAL Failed to configure CA instance: Command '/usr/sbin/pkispawn -s CA -f /tmp/tmpdVpOj5' returned non-zero exit status 1
2017-04-07T14:00:17Z CRITICAL See the installation logs and the following files/directories for more information:
2017-04-07T14:00:17Z CRITICAL   /var/log/pki/pki-tomcat
2017-04-07T14:00:17Z DEBUG Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/ipaserver/install/service.py", line 423, in start_creation
    run_step(full_msg, method)
  File "/usr/lib/python2.7/site-packages/ipaserver/install/service.py", line 413, in run_step
    method()
  File "/usr/lib/python2.7/site-packages/ipaserver/install/cainstance.py", line 624, in __spawn_instance
    nolog_list=(self.dm_password, self.admin_password, pki_pin)
  File "/usr/lib/python2.7/site-packages/ipaserver/install/dogtaginstance.py", line 148, in spawn_instance
    self.handle_setup_error(e)
  File "/usr/lib/python2.7/site-packages/ipaserver/install/dogtaginstance.py", line 395, in handle_setup_error
    raise RuntimeError("%s configuration failed." % self.subsystem)
RuntimeError: CA configuration failed.
```

The CA deployment scriptlel complains about existing directory, however this directory did not exist before calling ipa-ca-install:

```console
# ls /etc/pki/
CA  ca-trust  consumer  default.cfg  entitlement  java  nssdb  pki.conf  pki.version  rpm-gpg  rsyslog  tls
```

This seems to be a regression either in FreeIPA's configuration setup, or in Dogtag CA spawn machinery.

Versions:
```console
# rpm -q freeipa-server pki-ca
freeipa-server-4.5.0.dev201704071057+gitab27067-0.fc25.x86_64
pki-ca-10.3.5-11.fc25.noarch
```
Steps to reproduce:
1.) install CA-less ipa server w/ 3rd party HTTP/DS/PKINIT certificates
2.) ipa-ca-install -p DM_PASSWORD

Actual results:
Installation of Dogtag CA instance fails

Expected results:
CA is successfuly deployed and functional

Attached are the IPA CA install log and PKI CA instance spawn log.