clang scan-build: Fix "dead increment" warnings.

For the most part, these indicated a spot where the code could have
been better.

src/common/util.c

@@ -445,7 +445,7 @@ tor_log2(uint64_t u64)
     r += 2;
   }
   if (u64 >= (U64_LITERAL(1)<<1)) {
-    u64 >>= 1;
+    // u64 >>= 1; // not using this any more.
     r += 1;
   }
   return r;

src/or/directory.c

@@ -3823,7 +3823,6 @@ directory_handle_command_get,(dir_connection_t *conn, const char *headers,
   char *url, *url_mem, *header;
   time_t if_modified_since = 0;
   int zlib_compressed_in_url;
-  size_t url_len;
   unsigned compression_methods_supported;
 
   /* We ignore the body of a GET request. */
@@ -3854,12 +3853,13 @@ directory_handle_command_get,(dir_connection_t *conn, const char *headers,
   log_debug(LD_DIRSERV,"rewritten url as '%s'.", escaped(url));
 
   url_mem = url;
-  url_len = strlen(url);
+  {
+    size_t url_len = strlen(url);
 
-  zlib_compressed_in_url = url_len > 2 && !strcmp(url+url_len-2, ".z");
-  if (zlib_compressed_in_url) {
-    url[url_len-2] = '\0';
-    url_len -= 2;
+    zlib_compressed_in_url = url_len > 2 && !strcmp(url+url_len-2, ".z");
+    if (zlib_compressed_in_url) {
+      url[url_len-2] = '\0';
+    }
   }
 
   if ((header = http_get_header(headers, "Accept-Encoding: "))) {

src/or/routerparse.c

@@ -2934,7 +2934,7 @@ networkstatus_verify_bw_weights(networkstatus_t *ns, int consensus_method)
   }
 
   Wgg /= weight_scale;
-  Wgm /= weight_scale;
+  Wgm /= weight_scale; (void) Wgm; // unused from here on.
   Wgd /= weight_scale;
 
   Wmg /= weight_scale;
@@ -2942,8 +2942,8 @@ networkstatus_verify_bw_weights(networkstatus_t *ns, int consensus_method)
   Wme /= weight_scale;
   Wmd /= weight_scale;
 
-  Weg /= weight_scale;
-  Wem /= weight_scale;
+  Weg /= weight_scale; (void) Weg; // unused from here on.
+  Wem /= weight_scale; (void) Wem; // unused from here on.
   Wee /= weight_scale;
   Wed /= weight_scale;
 

src/test/test_hs_descriptor.c

@@ -90,6 +90,7 @@ test_cert_encoding(void *arg)
     pos += b64_cert_len;
     tt_int_op(strcmpstart(pos, "-----END ED25519 CERT-----"), OP_EQ, 0);
     pos += strlen("-----END ED25519 CERT-----");
+    tt_str_op(pos, OP_EQ, "");
   }
 
  done: