ncm-spma: dnf provider should allow switching to new stream when one is already active.

[aka7]

currently dnf provider allows setting of module stream, using the default config option.
Once a module is activated (through first install of a package from that stream), any changes to config to move to a later stream currently does nothing. The default will change to the most recent stream but active stream will still be the previous one. In order to move to the next stream, following command(s) will do it,

yum module reset <module_name>

and then running following do the update
yum distro-sync <module_name>

By just running module reset on config change will allow spma to find the newer packages on next spma run and will update as normal.

• The version of the component you are using (rpm -q $component)
  21.12.1-1
• What OS version you are using (/etc/redhat-release or similar)
  rhel8
• Steps required to reproduce the problem
• using nginx as example,
  install nginx from 1.18 stream.

set stream to 1.18

prefix "/software/modules";
"nginx/stream" = "1.18";
+prefix "/software";
+"packages" = pkg_add("nginx");

after spma run, should get nginx 1.18 installed, and stream 1.18 activated.

Now change the stream to 1.20.

+prefix "/software";
+"packages" = pkg_add("nginx");

next spma run will show no updates to perform for nginx.
nginx will still be 1.18, until currently following is run manually
module reset nginx

run spma again, and it update nginx.

• Actual result versus expected result
  actual: nginx still 1.18,
  expected: nginx to update to 1.20 from 1.20 stream.