Add all devstack nova instance types to F19 WordPress_NoKey

Add the m1.micro, m1.nano, and m1.xlarge instance types to the
WordPress_NoKey sample.  In the process, any devstack type that
requires atleast 2048MB of ram are mapped to i386 images, and those
requiring more are mapped to x86_64 images.

Change-Id: I48e696697436cfc820a91aa2096c94aec06cd769
Merge "Add all devstack nova instance types to F19 WordPress_NoKey"