Use finalize method in jinja2 to convert None values to empty strings

Fixes #4812
made accelerate keys directory configurable, and permissions for the file and dir configurable, and gave them a safe default
fixed file perms checking
fixed thinkoes
Fix typo
Merge pull request #5931 from suzaku/fix_typo

Fix typo in CODING_GUIDELINES.md
Merge branch 'devel' of https://github.com/xyrix/ansible into xyrix-devel
Specify mode in the makedirs call for fireball/accelerate keys
Merge branch 'issue_4812' into devel
Fix typos in ISSUE_TEMPLATE.md
Open LOG_LOCK file with FD_CLOEXEC to prevent file descriptor leakage

Fixes #5399
Merge pull request #5946 from bob-smith/patch-1

Fix typos in ISSUE_TEMPLATE.md
Micro-optimization of inventory.expand_hosts.detect_range
Micro-optimization: replace s.find(x)!=-1 with x in s

timeit shows a speedup of ~3x on Python 2.7.5 x86_64.
It also makes the code a bit shorter.
hostname module: don't filter hostnamectl with awk

There's no need to filter hostnamectl's output with awk because its man
page says:

    hostnamectl [OPTIONS...] {COMMAND}

       --static, --transient, --pretty
	   If status is used (or no explicit command is given) and one
	   of those fields is given, hostnamectl will print out just
           this selected hostname.

E.g. hostnamectl --static status => ansible.example.org