Makes dev_setup.py script more portable (#2062)

* Makes dev_setup.py script more portable

* Removes unused exec_command function

scripts/dev_setup.py

@@ -15,10 +15,10 @@
 root_dir = os.path.abspath(os.path.join(os.path.abspath(__file__), '..', '..'))
 
 
-def exec_command(command):
+def pip_command(command):
     try:
         print('Executing: ' + command)
-        check_call(command.split(), cwd=root_dir)
+        check_call([sys.executable, '-m', 'pip'] + command.split(), cwd=root_dir)
         print()
     except CalledProcessError as err:
         print(err, file=sys.stderr)
@@ -42,24 +42,24 @@ def exec_command(command):
 print('Root directory \'{}\'\n'.format(root_dir))
 
 # install general requirements
-exec_command('pip install -r requirements.txt')
+pip_command('install -r requirements.txt')
 
 # install packages
 for package_list in [nspkg_packages, content_packages]:
     for package_name in package_list:
-        exec_command('pip install -e {}'.format(package_name))
+        pip_command('install -e {}'.format(package_name))
 
 # install test requirements
-exec_command('pip install -r azure-sdk-testutils/test-requirements.txt')
+pip_command('install -r azure-sdk-testutils/test-requirements.txt')
 
-# isntall packaging requirements
-exec_command('pip install -r scripts/packaging_requirements.txt')
+# install packaging requirements
+pip_command('install -r scripts/packaging_requirements.txt')
 
 # install storage for tests
-exec_command('pip install azure-storage')
+pip_command('install azure-storage')
 
 # Ensure that the site package's azure/__init__.py has the old style namespace
 # package declaration by installing the old namespace package
-exec_command('pip install --force-reinstall azure-nspkg==1.0.0')
-exec_command('pip install --force-reinstall azure-mgmt-nspkg==1.0.0')
+pip_command('install --force-reinstall azure-nspkg==1.0.0')
+pip_command('install --force-reinstall azure-mgmt-nspkg==1.0.0')
 print('Finished dev setup.')