PEP 469 -- Migration of dict iteration code to Python 3
https://www.python.org/dev/peps/pep-0469/

str.rpartition rather than slice by len

It will be faster than call readlines_file().
timeit 1000 loops - more than 5 secs.

This reverts commit a70e52e2.
Back to original.

This reverts commit a5069b2d.
Back to 'with open' inside the function. It will be faster.

This reverts commit 332907e5.
Back to 'with open' inside the function. It will faster.

This reverts commit 00bcdcd9.

no need to write 'with open' once again

no need to write 'with open' once more
line_strip() removed from 'if' because it always returns True
readlines_files strip line but ' + '\n''  is part of the previous
code to create resolvconf

and yield line.strip() instead of do the strip after
each call to the function

This reverts commit f423d95e.

Signed-off-by: Holger Levsen <holger@layer-acht.org>

Signed-off-by: Holger Levsen <holger@layer-acht.org>

Signed-off-by: Holger Levsen <holger@layer-acht.org>

Signed-off-by: Holger Levsen <holger@layer-acht.org>