init-sig.sh: allow full image definition name customization

With Flatcar we would like to use different naming scheme as discussed
in flatcar/Flatcar#734, so this change
enables that. It brings no functional changes.

Signed-off-by: Mateusz Gozdek <mgozdekof@gmail.com>

images/capi/packer/azure/scripts/init-sig.sh

@@ -22,7 +22,7 @@ create_image_definition() {
   az sig image-definition create \
     --resource-group ${RESOURCE_GROUP_NAME} \
     --gallery-name ${GALLERY_NAME} \
-    --gallery-image-definition capi-${1} \
+    --gallery-image-definition ${1} \
     --publisher capz \
     --offer capz-demo \
     --sku ${2} \
@@ -34,38 +34,38 @@ SIG_TARGET=$1
 
 case ${SIG_TARGET} in
   ubuntu-1804)
-    create_image_definition ${SIG_TARGET} "18.04-LTS" "V1" "Linux"
+    create_image_definition capi-${SIG_TARGET} "18.04-LTS" "V1" "Linux"
   ;;
   ubuntu-2004)
-    create_image_definition ${SIG_TARGET} "20_04-lts" "V1" "Linux"
+    create_image_definition capi-${SIG_TARGET} "20_04-lts" "V1" "Linux"
   ;;
   centos-7)
-    create_image_definition "centos-7.7" "centos-7.7" "V1" "Linux"
+    create_image_definition "capi-centos-7.7" "centos-7.7" "V1" "Linux"
   ;;
   windows-2019)
-    create_image_definition "windows-2019-docker-ee" "win-2019-docker-ee" "V1" "Windows"
+    create_image_definition "capi-windows-2019-docker-ee" "win-2019-docker-ee" "V1" "Windows"
   ;;
   windows-2019-containerd)
-    create_image_definition ${SIG_TARGET} "win-2019-containerd" "V1" "Windows"
+    create_image_definition capi-${SIG_TARGET} "win-2019-containerd" "V1" "Windows"
   ;;
   windows-2022-containerd)
-    create_image_definition ${SIG_TARGET} "win-2022-containerd" "V1" "Windows"
+    create_image_definition capi-${SIG_TARGET} "win-2022-containerd" "V1" "Windows"
   ;;
   flatcar)
-    SKU="flatcar-${FLATCAR_CHANNEL}-${FLATCAR_VERSION}"
+    SKU="capi-flatcar-${FLATCAR_CHANNEL}-${FLATCAR_VERSION}"
     create_image_definition ${SKU} ${SKU} "V1" "Linux"
   ;;
   ubuntu-1804-gen2)
-    create_image_definition ${SIG_TARGET} "18.04-lts-gen2" "V2" "Linux"
+    create_image_definition capi-${SIG_TARGET} "18.04-lts-gen2" "V2" "Linux"
   ;;
   ubuntu-2004-gen2)
-    create_image_definition ${SIG_TARGET} "20_04-lts-gen2" "V2" "Linux"
+    create_image_definition capi-${SIG_TARGET} "20_04-lts-gen2" "V2" "Linux"
   ;;
   centos-7-gen2)
-    create_image_definition "centos-7.7-gen2" "centos-7.7-gen2" "V2" "Linux"
+    create_image_definition "capi-centos-7.7-gen2" "centos-7.7-gen2" "V2" "Linux"
   ;;
   flatcar-gen2)
-    SKU="flatcar-${FLATCAR_CHANNEL}-${FLATCAR_VERSION}-gen2"
+    SKU="capi-flatcar-${FLATCAR_CHANNEL}-${FLATCAR_VERSION}-gen2"
     create_image_definition "${SKU}" "${SKU}" "V2" "Linux"
   ;;
   *)