Merge pull request #413 from wkrause13/downloadFileFix

catch error in downloadFile

FS.common.js

@@ -287,7 +287,7 @@ var RNFS = {
   },
 
   read(filepath: string, length: number = 0, position: number = 0, encodingOrOptions?: any): Promise<string> {
-  	var options = {
+    var options = {
       encoding: 'utf8'
     };
 
@@ -483,6 +483,9 @@ var RNFS = {
         subscriptions.forEach(sub => sub.remove());
         return res;
       })
+      .catch(() => {
+        return Promise.reject(e);
+      })
     };
   },