configure: arrgh; mistakenly removed the alps version number

The alps component still exists; it shouldn't have been removed by
open-mpi/ompi@6c468b8691.

configure.ac

@@ -150,6 +150,7 @@ AC_SUBST(libmca_common_ofacm_so_version)
 AC_SUBST(libmca_common_sm_so_version)
 AC_SUBST(libmca_common_ugni_so_version)
 AC_SUBST(libmca_common_verbs_so_version)
+AC_SUBST(libmca_common_alps_so_version)
 
 #
 # Get the versions of the autotools that were used to bootstrap us