Fix more coverity warnings

Assorted minor code issues, which we should fix so any new errors stand
out more.

BUG=chromium:643769
BRANCH=none
TEST=make runtests

Change-Id: I82ece2de948ef224115c408bdfc09445d3da119b
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/390337
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

host/lib/host_misc.c

@@ -37,8 +37,10 @@ uint8_t* ReadFile(const char* filename, uint64_t* sizeptr) {
 
   fseek(f, 0, SEEK_END);
   size = ftell(f);
-  if (size < 0)
+  if (size < 0) {
+    fclose(f);
     return NULL;
+  }
   rewind(f);
 
   buf = malloc(size);