patman,buildman: remove redundant readlines() method

In Python, file objects can be used directly in iterators
without readlines() method.

The behavior is the same but it generally saves memory
without readlines().

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
patman: use raw strings for regular expression

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
buildman: Do not parse git aliase file