Removed check for include_trailing_comma for the Hanging Indent wrap mode

[bp72]

Closes #2174

When the wrap mode is Hanging Indent it doesn't make sense to take into consideration the value of include_trailing_comma. If we put the trailing comma it'll lead to a syntax error as described in the issue #2174.

An example of hanging indent wrap mode:

from third_party import \
    lib1, lib2, lib3, \
    lib4, lib5, lib6

[staticdev]

Thanks for the fix @bp72