configure.ac: bump .so version for next release

Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
diff --git a/configure.ac b/configure.ac
index 63590d1..76f67d9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -21,7 +21,7 @@
 # These numbers should be tweaked on every release. Read carefully:
 # http://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html
 # http://sourceware.org/autobook/autobook/autobook_91.html
-lt_current=1
+lt_current=2
 lt_revision=0
 lt_age=1
 LTLDFLAGS="-version-info ${lt_current}:${lt_revision}:${lt_age}"