Merge ~smoser/cloud-init:bug/1663723-ds-nocloud into cloud-init:master

[Scott Moser]

ds-identify: read ds=nocloud properly

The nocloud datasource specifically would look for ds=nocloud or
ds=nocloud-net (often augmented with 'seedfrom') on the kernel command line.
Fix to return DS_FOUND in that case.

LP: #1663723

[Server Team CI bot (server-team-bot)]

PASSED: Continuous integration, rev:f7bd9b3e10c6e289d214230c04320c538ca979e5
https://jenkins.ubuntu.com/server/job/cloud-init-ci/70/
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    SUCCESS: https://jenkins.ubuntu.com/server/job/cloud-init-ci/nodes=metal-s390x/70
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review: Approve (continuous-integration)

diff --git a/tools/ds-identify b/tools/ds-identify
index 88094af..e454ed6 100755
--- a/tools/ds-identify
+++ b/tools/ds-identify
@@ -514,6 +514,9 @@ dscheck_MAAS() {
 
 dscheck_NoCloud() {
     local fslabel="cidata" d=""
+    case " ${DI_KERNEL_CMDLINE} " in
+        *\ ds=nocloud*) return ${DS_FOUND};;
+    esac
     for d in nocloud nocloud-net; do
         check_seed_dir "$d" meta-data user-data && return ${DS_FOUND}
     done