Use free followed by malloc instead of realloc when increasing raw buffer

At this point we don't need to preserve the data inside the buffer.
Using free followed by malloc reduces fragmentation for some heap implementations.

Author: igrr

ssl/tls1.c

@@ -1402,15 +1402,19 @@ int basic_read(SSL *ssl, uint8_t **in_data)
 
 void increase_bm_data_size(SSL *ssl)
 {
-    uint8_t* pr = (uint8_t*) realloc(ssl->bm_all_data, RT_MAX_PLAIN_LENGTH + RT_EXTRA);
-    if (pr) {
-        ssl->max_plain_length = RT_MAX_PLAIN_LENGTH;
-        ssl->bm_all_data = pr;
-        ssl->bm_data = pr + BM_RECORD_OFFSET;
+    if (ssl->max_plain_length == RT_MAX_PLAIN_LENGTH) {
+        return;
     }
-    else {
+
+    free(ssl->bm_all_data);
+    ssl->bm_data = 0;
+    ssl->bm_all_data = malloc(RT_MAX_PLAIN_LENGTH + RT_EXTRA);
+    if (!ssl->bm_all_data) {
         printf("failed to grow plain buffer\r\n");
+        return;
     }
+    ssl->max_plain_length = RT_MAX_PLAIN_LENGTH;
+    ssl->bm_data = ssl->bm_all_data + BM_RECORD_OFFSET;
 }
 
 /**