pw_user: add 'user' arg to getent

Allows retrieval of user info for a single user, so it is not necessary
to iterate through the return data to get that user's info.

Also some pep8 fixes.
solaris_user: add 'user' arg to getent

Allows retrieval of user info for a single user, so it is not necessary
to iterate through the return data to get that user's info.

Also some pep8 fixes.
useradd: add 'user' arg to getent

Allows retrieval of user info for a single user, so it is not necessary
to iterate through the return data to get that user's info.

Also some pep8 fixes.
win_useradd: add 'user' arg to getent

Allows retrieval of user info for a single user, so it is not necessary
to iterate through the return data to get that user's info.

Also some pep8 fixes.
Make user state use updated user.getent function
Merge pull request #4133 from terminalmage/issue4059

Add 'user' arg to user.getent