Fix .alternates execution: it was skipping every second token.

R=r
APPROVED=r
DELTA=13  (11 added, 0 deleted, 2 changed)
OCL=34081
CL=34081

src/pkg/template/template.go

@@ -738,7 +738,7 @@ func (t *Template) executeRepeated(r *repeatedElement, st *state) {
 
 			// .alternates between elements
 			if !first && r.altstart >= 0 {
-				for i := r.altstart; i < r.altend; i++ {
+				for i := r.altstart; i < r.altend; {
 					i = t.executeElement(i, newst)
 				}
 			}
@@ -758,7 +758,7 @@ func (t *Template) executeRepeated(r *repeatedElement, st *state) {
 
 			// .alternates between elements
 			if !first && r.altstart >= 0 {
-				for i := r.altstart; i < r.altend; i++ {
+				for i := r.altstart; i < r.altend; {
 					i = t.executeElement(i, newst)
 				}
 			}

src/pkg/template/template_test.go

@@ -187,6 +187,17 @@ var tests = []*Test {
 
 		out: "this should appear: empty field\n"
 	},
+	&Test{
+		in: "{.repeated section pdata }\n"
+		"{item}\n"
+		"{.alternates with}\n"
+		"is\nover\nmultiple\nlines\n"
+		"{.end}\n",
+
+		out: "ItemNumber1\n"
+		"is\nover\nmultiple\nlines\n"
+		"ItemNumber2\n"
+	},
 	&Test{
 		in: "{.section pdata }\n"
 		"{.repeated section @ }\n"