Fix finding python2 interpreter on linux

indra/cmake/BuildPackagesInfo.cmake

indra/cmake/LLTestCommand.cmake

indra/cmake/Python.cmake

indra/cmake/TemplateCheck.cmake

indra/cmake/run_build_test.py

indra/copy_win_scripts/start-client.py

indra/fix-incredibuild.py

indra/lib/python/indra/util/test_win32_manifest.py

indra/llcorehttp/CMakeLists.txt

indra/llcorehttp/tests/test_llcorehttp_peer.py

indra/llmessage/tests/test_llsdmessage_peer.py

indra/llmessage/tests/testrunner.py

indra/newview/CMakeLists.txt

indra/newview/generate_breakpad_symbols.py

indra/newview/tests/test_llxmlrpc_peer.py

indra/newview/viewer_manifest.py

indra/test/test_llmanifest.py