Do not require the vim package to be installed

The minimal Ubuntu image used on GKE nodes provides the vim editor as
part of system packages, as "vim.tiny". People logging on the nodes have a vim
environment available despite the "vim" package not being installed.

Signed-off-by: Chris Glass <chris.glass@canonical.com>

test/e2e_node/system/specs/gke.yaml

@@ -235,8 +235,6 @@ packageSpecs:
   versionRange: '>=1.28'
 - name: util-linux
   versionRange: '>=2.27.1'
-- name: vim
-  versionRange: '>=7.4.712'
 - name: wget
   versionRange: '>=1.18'
 - name: gce-compute-image-packages