[plugins] Makefile.am is written to support only builtin plugins

So, workaround is to build builtin plugins as builtin and dynamic can
be built as dynamic.

TODO: Makefile.am need to be fixed to correctly build dynamic in-tree
plugins

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[rpm] enable curl back

This reverts commit 8e7246d9cf22a401cb74ee180db048818e45add6.

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
rpm: --disable-capng is not used

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
Merge pull request #3 from deztructor/master

workaround: in-tree plugins can be built only as builtin