Update source/applications/gridfs.txt

Corrected typo: "You also can access information from arbitrate sections of files" become "You also can access information from arbitrary sections of files"

Author: glennstreet

source/applications/gridfs.txt

@@ -19,7 +19,7 @@ collection stores the file chunks, and the other stores file metadata.
 When you query a GridFS store for a file, the driver or client will
 reassemble the chunks as needed. You can perform range queries on
 files stored through GridFS.  You also can access information from
-arbitrate sections of files, which allows you to "skip" into the
+arbitrary sections of files, which allows you to "skip" into the
 middle of a video or audio file.
 
 GridFS is useful not only for storing files that exceed 16MB but also