git: Make function get_remote_head usable when cloning.

This allows the module to return the before/after revisions in all cases.
git: Always return the before/after revisions, even in check mode.

The return values from check mode and non-check mode should match in all cases,
except when a SHA-1 hash is used as version, as there is no way to check if it
is a valid hash using `git ls-remote`.

Also, to accomodate this change, the force flag for the reset function has been
removed so that we can do the checking in main.
git: Handle network problem when running `git ls-remote`.
git: Don't add --branch while cloning if the version is a SHA-1 hash.
Merge pull request #4538 from mulby/gabe/arguments-sudo

Ensure non-root users can read arguments file when using sudo_user and non-standard modules
Fixes #4301 Use module_common functions for mysqldump and return better errors
mysql_db: if connection is a socket, do not specify hostname
Throw a more user-friendly exception during template rendering process.
s3: better check for walrus

Check for Walrus endpoint by looking to see if the endpoint is not AWS.

This fixes a bug where the user specifies an AWS endpoint via S3_URL,
but the code interprets it as Walrus and then fails.
apt_key: Validate key_id and accept a leading '0x'
Merge pull request #4543 from lorin/s3-walrus

s3: better check for walrus
when searching for a plugin only look for a regular file
Merge pull request #4544 from mmoya/features

apt_key: Validate key_id and accept a leading '0x'
Merge pull request #4547 from stoned/find_plugin-fix

when searching for a plugin only look for a regular file
Fix 'ansible-doc -l' runtime error following commit 4430d0f

skip "module" not found as plugin, id est directory
Merge pull request #4548 from stoned/ansible-doc-fix

Fix 'ansible-doc -l' runtime error following commit 4430d0f
Fixes #4350 Create homedirectory if create=yes and directory is missing
Merge pull request #4428 from robparrott/devel

Properly handle DEFAULT section with ConfigParser in ini_file modules
Merge pull request #4480 from joemaller/absent_path_fix

ignore src when file module state=absent
Merge pull request #4517 from adfinis-sygroup/devel

Remove keys regardless of the options