Build static libraries for libevent on host and device.

It is used by simpleperf.

Bug: http://b/30405638
Change-Id: I3fa75ab5f36b2153fd5e72e05e3d054ff35d864e
diff --git a/Android.bp b/Android.bp
index 3b9d52b..bad0ea3 100644
--- a/Android.bp
+++ b/Android.bp
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-cc_library_shared {
+cc_library {
     name: "libevent",
     host_supported: true,
     unique_host_soname: true,