[libhandy] flap: Fix minimum size calculation

[Alexander Mikhaylenko <alexm src gnome org>]

commit 9c64f9fe37f569da70db132d08671bf946ebe3c2
Author: Benjamin Schaaf <ben schaaf gmail com>
Date:   Wed Jan 20 23:50:19 2021 +1100

    flap: Fix minimum size calculation

 src/hdy-flap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/hdy-flap.c b/src/hdy-flap.c
index 8d8f375e..d9737638 100644
--- a/src/hdy-flap.c
+++ b/src/hdy-flap.c
@@ -738,7 +738,7 @@ compute_sizes (HdyFlap       *self,
 
   extra = total - *content_size - *flap_size;
 
-  if (flap_expand) {
+  if (extra > 0 && flap_expand) {
     *flap_size += extra;
     extra = 0;
 
@@ -748,7 +748,7 @@ compute_sizes (HdyFlap       *self,
     return;
   }
 
-  if (content_expand) {
+  if (extra > 0 && content_expand) {
     *content_size += extra;
     extra = 0;
   }