Fix exponential regex performance issue

filter_leading_non_json_lines effectively does

re.match(".*\w+=\w+.*", line)

for every line of output. This has abysmal performance in case of large
Base64-encoded data (which ultimately does not match the regex but does
match the .*\w+= part) as returned e.g. by the template module (diffs).

Replacing the match with

re.search("\w=\w", line)

drops the complexity back to linear, and actually usable with large
diffs from the template module (a 150 KB Base64 diff kept Ansible
spinning at 100% cpu for minutes).

Also, check the easy cases (line.startswith) first while we're here.

Closes: #8932
Merge branch 'bug8392' of git://github.com/gnosek/ansible into devel
Add some whitespace to make paramiko_ssh more browseable
Use atomic move function on known host file in paramiko to prevent rare occurance of Control-C
during file operations.
Remove unnecessary unicode conversions from parse_kv

Fixes #8425
Revert ""allow_no_value=True" for ini_file module so /etc/my.cnf can be read without a problem"

This reverts commit cbdc9f1153e665fe0e62a11ed7c244adb83ecbd9.

Code needs to make allowances for particular python versions and try/except
around this block.