Don't create log directory and empty crash.log under PWD

[shino]

Executing cuttlefish escript creates empty log/crash.log file under working directory.

% ls
Makefile  README.md  cuttlefish  deps  ebin  priv  rebar  rebar.config  src  test  test_fixtures  tools.mk
% ./cuttlefish -h
Usage: ./cuttlefish [-h] [-e <etc_dir>] [-d <dest_dir>] [-f <dest_file>] [-s <schema_dir>] [-i <schema_file>] [-c <conf_file>] [-a <app_config>] [-l <log_level>] [-p] [-m <max_history>]
[snip more output]
% ls
Makefile  README.md  cuttlefish  deps  ebin  log  priv  rebar  rebar.config  src  test  test_fixtures  tools.mk

Background:

After installing riak-cs package and execute riak-cs start, there is a file /usr/lib/riak-cs/log/crash.log. It is almost harmless but unconfortable because /usr/lib/riak-cs/ is usually considered as read only.

[shino]

@borshop merge