Fix clang warnings in applications

Some fd would be used uninitialized if we goto exit early.
diff --git a/programs/ssl/ssl_client1.c b/programs/ssl/ssl_client1.c
index d6e712b..e09ad8c 100644
--- a/programs/ssl/ssl_client1.c
+++ b/programs/ssl/ssl_client1.c
@@ -74,7 +74,7 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret, len, server_fd;
+    int ret, len, server_fd = -1;
     unsigned char buf[1024];
     const char *pers = "ssl_client1";