inspector: inject cargo dependency in runtime

Fixes: https://pagure.io/fedora-rust/rust2rpm/issue/42
Signed-off-by: Igor Gnatenko <ignatenkobrain@fedoraproject.org>

rust2rpm/__main__.py

@@ -91,6 +91,7 @@ Provides:       {{ prv }}
 {% endfor %}
 {% endif %}
 {% if include_requires %}
+Requires:       cargo
 {% if md.requires|length > 0 %}
 # [dependencies]
 {% for req in md.requires|sort(attribute="name") %}

rust2rpm/inspector.py

@@ -38,6 +38,9 @@ def main():
             print_deps(list(itertools.chain(md.requires, md.build_requires)))
         if args.test_requires:
             print_deps(md.test_requires)
+        if args.requires:
+            # Someone should own /usr/share/cargo/registry
+            print("cargo")
 
 if __name__ == "__main__":
     main()