Fixed ndk version check when no version found

Author: inclement

pythonforandroid/recommendations.py

@@ -53,6 +53,7 @@ def read_ndk_version(ndk_dir):
     else:
         info('Could not parse $NDK_DIR/source.properties, not checking '
              'NDK version')
+        return
 
     # Line should have the form "Pkg.Revision = ..."
     ndk_version = LooseVersion(line.split('=')[-1].strip())