perf script python: Remove explicit shebang from Python scripts

perf script python: Remove explicit shebang from Python scripts

The scripts in scripts/python are intended to be run from 'perf script'
and the Python version used is dictated by how perf was built (PYTHON=).

Also most distros follow pep-0394 which recommends that /usr/bin/python
refer to Python2 and so may not exist on the system (if PYTHON=python3).

- Remove the explicit shebang
- Install the scripts as mode 644

Signed-off-by: Tony Jones <tonyj@suse.de>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Seeteena Thoufeek <s1seetee@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20190124005229.16146-6-tonyj@suse.de
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>