update regex used by rpm build to find lib files

update regex used by rpm build to find lib files

The old expression was '*.so.*.*.*' to find shared library
files with 3 components in the version.

Building from master gives you files with 2 components in
the version (e.g. libvnet.so.18.10). So most libs were not
getting included in vpp-lib.

Change-Id: Ib89d2f5aeb2417eed1b6b851089b9d22f540a226
Signed-off-by: Matthew Smith <mgsmith@netgate.com>