Skip non-zip files when refreshing build library

Test: th
Change-Id: I16631183c40136c4603f20e2ea07664123338da4
diff --git a/tools/otagui/target_lib.py b/tools/otagui/target_lib.py
index db9ab9e..bfc68d5 100644
--- a/tools/otagui/target_lib.py
+++ b/tools/otagui/target_lib.py
@@ -130,8 +130,9 @@
         if os.path.isdir(path):
             builds_name = os.listdir(path)
             for build_name in builds_name:
-                self.new_build(build_name, os.path.join(path, build_name))
-        elif os.path.isfile(path):
+                if build_name.endswith(".zip"):
+                    self.new_build(build_name, os.path.join(path, build_name))
+        elif os.path.isfile(path) and path.endswith(".zip"):
             self.new_build(os.path.split(path)[-1], path)
         return self.get_builds()