Fix S3_ENDPOINT (#798)
Fix S3_ENDPOINT (#798)

Broken by 04bc143b7e11f5b448278d05fd84d68d28503c88
quiltdata/quilt,quiltdata/quilt,quiltdata/quilt,quiltdata/quilt,quiltdata/quilt-compiler,quiltdata/quilt-compiler,quiltdata/quilt,quiltdata/quilt-compiler,quiltdata/quilt-compiler