spec: rename the bootc-reinstall subpackage

The subpackage name was left to be bootc-reinstall even though we
decided on a name change.

This commit changes the package name to match the binary name which is `system-reinstall-bootc`

# Implementation

By default .spec files will prepend the main package name to the
subpackage name, the `-n` flag of the `%package` directive prevents that

Signed-off-by: Omer Tuchfeld <omer@tuchfeld.dev>

Author: omertuc

contrib/packaging/bootc.spec

@@ -62,7 +62,8 @@ Provides: ostree-cli(ostree-container)
 %description
 %{summary}
 
-%package reinstall
+# (-n because we don't want the subpackage name to start with bootc-)
+%package -n system-reinstall-bootc
 Summary: Utility to reinstall the current system using bootc
 Requires: podman
 # The reinstall subpackage intentionally does not require bootc, as it pulls in many unnecessary dependencies