Change serveradmin default to undef

`serveradmin` is expecting a string, but defaults to `false`. It should
be `undef` to match all the other string parameter defaults.
Release 0.11.0

Summary:

This release adds preliminary support for Windows compatibility and multiple rewrite support.

Backwards-incompatible Changes:

- The rewrite_rule parameter is deprecated in favor of the new rewrite parameter
  and will be removed in a future release.

Features:

- add Match directive
- quote paths for windows compatibility
- add auth_group_file option to README.md
- allow AuthGroupFile directive for vhosts
- Support Header directives in vhost context
- Don't purge mods-available dir when separate enable dir is used
- Fix the servername used in log file name
- Added support for mod_include
- Remove index parameters.
- Support environment variable control for CustomLog
- added redirectmatch support
- Setting up the ability to do multiple rewrites and conditions.
- Convert spec tests to beaker.
- Support php_admin_(flag|value)s

Bugfixes:

- directories are either a Hash or an Array of Hashes
- Configure Passenger in separate .conf file on RH so PassengerRoot isn't lost
- (docs) Update list of `apache::mod::[name]` classes
- (docs) Fix apache::namevirtualhost example call style
- Fix $ports_file reference in apache::listen.
- Fix $ports_file reference in Namevirtualhost.
Fix typos in templates/vhost/_itk.erb

Basically, this wouldn't have worked because of mass typos. FTFY
Merge pull request #599 from hunner/serveradmin_default

Change serveradmin default to undef
Merge pull request #601 from hunner/fix_itk

Fix typos in templates/vhost/_itk.erb
Merge pull request #600 from blkperl/release_011

Release 0.11.0 NOW do README stuff later as bugfix
Fix typo in mod passenger documentation

The rails_auto_detect and rack_auto_detect should not have an underscore between auto and detect.
Merge pull request #611 from ubergeek42/patch-1

Fix typo in mod passenger documentation
Added apache24 support
Fix to lots of tests to work with apache24
Apache24 on Ubuntu SSL to use default mutex

Changed the ssl module to use default for the new Mutex with Apache 2.4
on Ubuntu
Merge pull request #552 from smitherz82/apache24_support

Apache2.4 support
Ensure socache_shmcb is enabled on all Apache 2.4 OSes

The SSLSessionCache option is specified as socache_shmcb, so the module must
be enabled.
Merge pull request #612 from domcleal/f19-ssl

Ensure socache_shmcb is enabled on all Apache 2.4 OSes
fix simple linting errors
disable lint check for "single quoted variables"

Previously we were checking (and failing every linting run) because
the values for Debian configurations uses a syntax that looks like
Puppet variables.  This is regrettable since it's a valuable check but
the fix will probably require changing how the conf variables are
handled which is out of the scope of this PR.
use a .puppet-lint.rc for usage outside of rake tasks
Add WSGIApplicationGroup and WSGIImportScript directives
Add WSGIApplicationGroup & WSGIImportScript tests.
Merge pull request #606 from bodgit/wsgi

Add WSGIApplicationGroup and WSGIImportScript directives