fix: resolve cppcheck shadow/always-true findings

src/shared/credentials.c

@@ -141,9 +141,9 @@ static FILE* secret_file_open(const char* path, char* err, size_t err_size) {
    * most systems, but explicit.  Failures here are ignored: O_NONBLOCK on a
    * regular file does not affect reads either way. */
   if (S_ISREG(st.st_mode)) {
-    int flags = fcntl(fd, F_GETFL);
-    if (flags >= 0)
-      (void)fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
+    int status_flags = fcntl(fd, F_GETFL);
+    if (status_flags >= 0)
+      (void)fcntl(fd, F_SETFL, status_flags & ~O_NONBLOCK);
   }
   FILE* fp = fdopen(fd, "r");
   if (!fp) {

tests/test_file.c

@@ -411,7 +411,6 @@ static void test_file_open_temp_dir_symlink_confinement() {
   EXPECT_EQ_INT(mkdir(scratch, 0755), 0);
   int scratch_fd = file_open_temp_dir(scratch);
   EXPECT_TRUE(scratch_fd >= 0);
-  if (scratch_fd >= 0)
   close(scratch_fd);
 
   /* A symlink whose target is outside the root is refused. */
@@ -426,7 +425,6 @@ static void test_file_open_temp_dir_symlink_confinement() {
   EXPECT_EQ_INT(symlink(scratch, inside_link), 0);
   int link_fd = file_open_temp_dir(inside_link);
   EXPECT_TRUE(link_fd >= 0);
-  if (link_fd >= 0)
   close(link_fd);
 
   free(inside_link);