GUI changes

[wimpers]

Please make following changes to the Backend detail page in the GUI:

• Local backend: the piechart should display Metadata, Used and Free.
• Global backend: remove pie chat all together.

Feel free to optimize the code so the pages load faster (due to the vPool details not being fetched)

[kvanhijf]

Pie chart for ALBA backends of type LOCAL is now as following:

• Free space (Total size reported by ASDs - total size used reported by ASDs)
• Used space (Total size used as reported by alba show-namespace statistics)
• Internal metadata (Total size used reported by ASDs - total size used as reported by alba show-namespace statistics)

[kinvaris]

PASSED:

ii  openvstorage                       2.7.2-rev.3867.ec9d46d-1                                 amd64        openvStorage
ii  openvstorage-backend               1.7.2-rev.675.37ca5b8-1                                  amd64        openvStorage Backend plugin
ii  openvstorage-backend-core          1.7.2-rev.675.37ca5b8-1                                  amd64        openvStorage Backend plugin core
ii  openvstorage-backend-webapps       1.7.2-rev.675.37ca5b8-1                                  amd64        openvStorage Backend plugin Web Applications
ii  openvstorage-cinder-plugin         1.2.2-rev.32.948a8c1-1                                   amd64        OpenvStorage Cinder plugin for OpenStack
ii  openvstorage-core                  2.7.2-rev.3867.ec9d46d-1                                 amd64        openvStorage core
ii  openvstorage-hc                    1.7.2-rev.675.37ca5b8-1                                  amd64        openvStorage Backend plugin HyperConverged
ii  openvstorage-sdm                   1.6.2-rev.330.f06c8de-1                                  amd64        Open vStorage Backend ASD Manager
ii  openvstorage-webapps               2.7.2-rev.3867.ec9d46d-1                                 amd64        openvStorage Web Applications