make output of function get_pathman_lib_version() more user-friendly

Author: funbringer

expected/pathman_calamity.out

@@ -13,7 +13,7 @@ SELECT debug_capture();
 SELECT get_pathman_lib_version();
  get_pathman_lib_version 
 -------------------------
- 10410
+ 1.4.10
 (1 row)
 
 set client_min_messages = NOTICE;

src/pl_funcs.c

@@ -1606,5 +1606,9 @@ debug_capture(PG_FUNCTION_ARGS)
 Datum
 get_pathman_lib_version(PG_FUNCTION_ARGS)
 {
-	PG_RETURN_CSTRING(psprintf("%x", CURRENT_LIB_VERSION));
+	uint8	ver_major = (CURRENT_LIB_VERSION & 0xFF0000) >> 16,
+			ver_minor = (CURRENT_LIB_VERSION & 0xFF00) >> 8,
+			ver_patch = (CURRENT_LIB_VERSION & 0xFF);
+
+	PG_RETURN_CSTRING(psprintf("%x.%x.%x", ver_major, ver_minor, ver_patch));
 }