conda_build/source.py: Instead of checking `encoding` multiple times. Simply verify that `encoding` is set to something or force it to `utf-8` before proceeding.
conda_build/source.py: Instead of checking `encoding` multiple times. Simply verify that `encoding` is set to something or force it to `utf-8` before proceeding.

rmcgibbo/conda-build,rmcgibbo/conda-build,rmcgibbo/conda-build,dan-blanchard/conda-build,sandhujasmine/conda-build,dan-blanchard/conda-build,mwcraig/conda-build,ilastik/conda-build,dan-blanchard/conda-build,ilastik/conda-build,ilastik/conda-build,mwcraig/conda-build,sandhujasmine/conda-build,sandhujasmine/conda-build,mwcraig/conda-build