Accepting request 289785 from home:pluskalm:branches:network

- Cleanup spec-file with spec-cleaner
- Do not generate config.example from README
  * add config.example as source
- Add unit file (nbd-server.service)
- Add sysconfig template (nbd-server.sysconfig)
- Add no-return-nonvoid.patch
- Update requirements
- Update to 3.9

OBS-URL: https://build.opensuse.org/request/show/289785
OBS-URL: https://build.opensuse.org/package/show/network:utilities/nbd?expand=0&rev=27

config.example

@@ -0,0 +1,33 @@
+[generic]
+        # The [generic] section is required, even if nothing is specified
+        # there.
+        # When either of these options are specified, nbd-server drops
+        # privileges to the given user and group after opening ports, but
+        # _before_ opening files.
+        user = nbd
+        group = nbd
+        # Since version 2.9.17, nbd-server will do exports on a name
+        # basis (the used name is the name of the section in which the
+        # export is specified). This however required an incompatible
+        # protocol change. To enable backwards-compatible port-based
+        # exports, uncomment the following line:
+        # oldstyle = true
+[export1]
+        exportname = /export/nbd/export1-file
+        # The following line will be ignored unless the
+        # "oldstyle = true" line in the generic section above is
+        # enabled.
+        port = 12345
+        authfile = /export/nbd/export1-authfile
+        timeout = 30
+        filesize = 10000000
+        readonly = false
+        multifile = false
+        copyonwrite = false
+        prerun = dd if=/dev/zero of=%s bs=1k count=500
+        postrun = rm -f %s
+[otherexport]
+        exportname = /export/nbd/experiment
+        # The other options are all optional, except this one in case
+        # the oldstyle option is used in [generic]:
+        # port = 12346