buf_string_match_head_str: Fix Coverity issue 'Unsigned compared agai…

…nst 0'

As Coverity says:
An unsigned value can never be negative, so this test will always
evaluate the same way.

Was changed from int to size_t in commit
7fc608d which triggered warning,
but the check did not make sense before, either.

Change-Id: I64f094eeb0ca8c3953a94d742adf468faf27dab3
Signed-off-by: Frank Lichtenheld <[email protected]>
Acked-by: Arne Schwabe <[email protected]>
Message-Id: <[email protected]>
URL: https://www.mail-archive.com/[email protected]/msg28093.html
Signed-off-by: Gert Doering <[email protected]>

src/openvpn/buffer.c

@@ -822,7 +822,7 @@ bool
 buf_string_match_head_str(const struct buffer *src, const char *match)
 {
     const size_t size = strlen(match);
-    if (size < 0 || size > src->len)
+    if (size > src->len)
     {
         return false;
     }