Include flannel version in flannel cni plugin version

We were misreporting the flannel version as the flannel cni plugin version; restore the actual flannel version as build metadata

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
(cherry picked from commit 6f331ea7b5)
Signed-off-by: Brad Davidson <brad.davidson@rancher.com>

scripts/build

@@ -41,7 +41,7 @@ VERSIONFLAGS="
 
     -X ${PKG_CNI_PLUGINS}/pkg/utils/buildversion.BuildVersion=${VERSION_CNIPLUGINS}
     -X ${PKG_CNI_PLUGINS}/plugins/meta/flannel.Program=flannel
-    -X ${PKG_CNI_PLUGINS}/plugins/meta/flannel.Version=${VERSION_FLANNEL_PLUGIN}
+    -X ${PKG_CNI_PLUGINS}/plugins/meta/flannel.Version=${VERSION_FLANNEL_PLUGIN}+${VERSION_FLANNEL}
     -X ${PKG_CNI_PLUGINS}/plugins/meta/flannel.Commit=HEAD
     -X ${PKG_CNI_PLUGINS}/plugins/meta/flannel.buildDate=${buildDate}