treat no ndk_version as < 22

Author: obfusk

pythonforandroid/build.py

@@ -399,7 +399,7 @@ def prepare_build_environment(self,
         arch = self.archs[0]
         toolchain_prefix = arch.toolchain_prefix
         ndk_version = read_ndk_version(ndk_dir)
-        if ndk_version is not None and ndk_version < LooseVersion('22'):
+        if ndk_version is None or ndk_version < LooseVersion('22'):
             self.ndk_platform, ndk_platform_dir_exists = get_ndk_platform_dir(
                 self.ndk_dir, self.ndk_api, arch)
             ok = ok and ndk_platform_dir_exists