Do not eagerly initialize BlobStore

This prevents OpenStack blobstores from matching regions incorrectly, basing on a value of the endpoint variable. OVH has different URLs for each storage endpoint, which does not match the auth endpoint.

src/main/java/org/gaul/s3proxy/Main.java

@@ -310,11 +310,13 @@ public final class Main {
         }
 
         BlobStoreContext context = builder.build(BlobStoreContext.class);
-        BlobStore blobStore = context.getBlobStore();
+        BlobStore blobStore;
         if (context instanceof RegionScopedBlobStoreContext &&
                 region != null) {
             blobStore = ((RegionScopedBlobStoreContext) context)
                     .getBlobStore(region);
+        } else {
+            blobStore = context.getBlobStore();
         }
         return blobStore;
     }