fix crash when all value fields of imported table are uninitialized.

testing/btest/Baseline/scripts.base.frameworks.input.emptyvals/out

@@ -0,0 +1,4 @@
+{
+[2] = [b=<uninitialized>],
+[1] = [b=T]
+}

testing/btest/scripts/base/frameworks/input/emptyvals.bro

@@ -0,0 +1,37 @@
+#
+# @TEST-EXEC: bro %INPUT >out
+# @TEST-EXEC: btest-diff out
+
+@TEST-START-FILE input.log
+#separator \x09
+#path	ssh
+#fields	b	i
+##types	bool	int
+T	1
+-	2
+@TEST-END-FILE
+
+redef InputAscii::empty_field = "EMPTY";
+
+module A;
+
+type Idx: record {
+	i: int;
+};
+
+type Val: record {
+	b: bool;
+};
+
+global servers: table[int] of Val = table();
+
+event bro_init()
+{
+	# first read in the old stuff into the table...
+	Input::add_table([$source="input.log", $name="ssh", $idx=Idx, $val=Val, $destination=servers]);
+	Input::remove("ssh");
+}
+
+event Input::update_finished(name: string, source:string) {
+	print servers;
+}