meson: Don't require sdbusplus to be built shared

It will build the shared library by default, but will allow us to do
static builds if we want.

Change-Id: Id45d3988e4bfa5f0693c4f7b11f576a9c9421826
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meson.build b/meson.build
index a965d14..caf8c01 100644
--- a/meson.build
+++ b/meson.build
@@ -16,7 +16,7 @@
     'sdbusplus/server/transaction.cpp',
 )
 
-libsdbusplus = shared_library(
+libsdbusplus = library(
     'sdbusplus',
     libsdbusplus_src,
     dependencies: libsystemd_pkg,