Fix rst2man reference and python shebangs

Also remove obsolete Group tag.

python-avocado.spec

@@ -36,7 +36,7 @@ Name: python-%{pkgname}
 Version: 52.1
 Release: 7%{?gitrel}%{?dist}
 Summary: Framework with tools and libraries for Automated Testing
-Group: Development/Tools
+
 # Found licenses:
 # avocado/utils/external/gdbmi_parser.py: MIT
 # avocado/utils/external/spark.py: MIT
@@ -55,9 +55,10 @@ Patch1: avocado-selftest-fix-cmdline-check.patch
 BuildArch: noarch
 BuildRequires: python2-aexpect
 BuildRequires: python2-devel
-BuildRequires: python2-docutils
 BuildRequires: python2-mock
 BuildRequires: python2-resultsdb_api
+BuildRequires: /usr/bin/rst2man
+BuildRequires: grep, sed
 
 %if 0%{?fedora} > 27 || 0%{?rhel} > 7
 BuildRequires: python2-flexmock
@@ -293,6 +294,8 @@ sed -e "s/'libvirt-python'//" -i optional_plugins/runner_vm/setup.py
 sed -e "s/'fabric'/'fabric3'/" -i optional_plugins/runner_remote/setup.py
 %endif
 
+grep -r -l '/usr/bin/env python' . | xargs sed -i 's|/usr/bin/env python|%__python2|'
+
 %build
 %{__python2} setup.py build
 pushd optional_plugins/html