Boulder inserts empty name() deps when empty rundeps present

[davidjharder]

When a stone.yaml includes an empty rundep like:

rundeps    :
    -  tree
    -
networking  : yes

or:

rundeps    :
    -
networking  : yes

or:

rundeps    :
    #- tree
networking  : yes

or:

rundeps    :
 
networking  : yes

boulder obligingly creates a dependency that will fail on install:

 ⚠  Unable to install due to the following problems...

 - [MissingDependency] name(null)