build: correct libtool parameter used within Makefiles

This corrects the parameters passed to libtool when linking
the shared libraries. The paramter name is -version-info not
-version.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/ospfd/Makefile.am b/ospfd/Makefile.am
index f968d7d..4e1a4fe 100644
--- a/ospfd/Makefile.am
+++ b/ospfd/Makefile.am
@@ -5,7 +5,7 @@
 INSTALL_SDATA=@INSTALL@ -m 600
 
 lib_LTLIBRARIES = libospf.la
-libospf_la_LDFLAGS = -version 0:0:0
+libospf_la_LDFLAGS = -version-info 0:0:0
 
 sbin_PROGRAMS = ospfd