Add --file to image-update and correct bad name

* Add the --file option to the image-update action, as it was left out
  of a previous patch
* Additionally, change a bad reference (args.fields) to args.file
* Fix bug 1022750

Change-Id: Idde127ec3f138f718d671b2133d50debec26236e

glanceclient/v1/shell.py

@@ -92,8 +92,8 @@ def do_image_show(gc, args):
                  ' you would specify \'file:///usr/share/image.tar.gz\'.'))
 @utils.arg('--file', metavar='<FILE>',
            help=('Local file that contains disk image to be uploaded during'
-                 ' creation or update.  Alternatively, images can be passed to'
-                 ' the client via stdin.'))
+                 ' creation. Alternatively, images can be passed to the client'
+                 ' via stdin.'))
 @utils.arg('--checksum', metavar='<CHECKSUM>',
            help='Hash of image data used Glance can use for verification.')
 @utils.arg('--copy-from', metavar='<IMAGE_URL>',
@@ -153,6 +153,10 @@ def do_image_create(gc, args):
                  ' For example, if the image data is stored in the filesystem'
                  ' local to the glance server at \'/usr/share/image.tar.gz\','
                  ' you would specify \'file:///usr/share/image.tar.gz\'.'))
+@utils.arg('--file', metavar='<FILE>',
+           help=('Local file that contains disk image to be uploaded during'
+                 ' update. Alternatively, images can be passed to the client'
+                 ' via stdin.'))
 @utils.arg('--checksum', metavar='<CHECKSUM>',
            help='Hash of image data used Glance can use for verification.')
 @utils.arg('--copy-from', metavar='<IMAGE_URL>',
@@ -183,7 +187,7 @@ def do_image_update(gc, args):
     fields = dict(filter(lambda x: x[0] in UPDATE_PARAMS, fields.items()))
 
     if 'location' not in fields and 'copy_from' not in fields:
-        if args.fields:
+        if args.file:
             fields['data'] = open(args.file, 'r')
         else:
             fields['data'] = sys.stdin