Handle access error when writing binary to cache

I'm not sure why the throw isn't being caught. Probably some async
thing. Don't have time to look into it atm.

scripts/install.js

@@ -137,7 +137,9 @@ function checkAndDownloadBinary() {
         mkdir.sync(path.dirname(cachedBinary));
         fs.createReadStream(binaryPath)
           .pipe(fs.createWriteStream(cachedBinary))
-          .on('error', function (e) { throw e; });
+          .on('error', function (e) {
+            log.error('node-sass install', 'Failed to cache binary: %s', err);
+          });
       } catch (err) {
         log.error('node-sass install', 'Failed to cache binary: %s', err);
       }