Removed no explicit interpreter optimization

In rare cases, files that are installed via a setup.py seem to get their
executable bit set (even when they shouldn't). This causes the
emr._executable method to assume they are executable and causes it to
skip adding the interepretter to the command to be exectuted. If the
script in questions lacks (or has an incorrect) #! line then the job
will fail.

I decided the best way to fix this is safety first and always include
the interpreter.

Signed-off-by: Tim Henderson <tim.tadh@gmail.com>
Fix urlparse import in mrjob.fs.s3
Merge pull request #685 from irskep/fix-a-urlparse-import

Fix urlparse import in mrjob.fs.s3
Normalize urlparse behavior for s3, s3n, hdfs, mapreduce url schemes for all Python versions
Better solution to py2.7.4 urlparse behavior fix
Support allow_fragments in mrjob.parse.urlparse()
Reinstate @wraps, future proof against extremely unlikely func sig changes
Merge pull request #686 from irskep/fix-urlparse-2.7.4

Normalize urlparse fragment behavior across all supported Python versions
Merge pull request #683 from timtadh/bug/exec-get-steps-os-error-8

Bug/exec get steps os error 8
added avshkop to __credits__, bumped version to 0.4.1-dev
mrjob.__credits__: jbrown has moved on to uber.com
Update Steve Johnson's email in __credits__
ripped out class-based protocols (fixes #486)
updated protocol tests to use instances
fixed test_job
PEP8ing as long as I'm touching this file
use "self", not "cls"
Merge pull request #698 from davidmarin/make_protocols_instances

Make protocols instances
Update wqardaji's email in __credits__
Partially functional sphinx extension