Avoid bogus gcc warning

Recent gcc/glibc combinations warn about ignoring the fgets() result.
The problem exists on Ubuntu 9.10 with current updates. This "fix" of
the non-problem (as I check ferror() afterwards) should even be a
(negligible) performance optimization.

Corresponding to flashrom svn r884.

Signed-off-by: Michael Karcher <flashrom@mkarcher.dialup.fu-berlin.de>
Acked-by: Andrew Morgan <ziltro@ziltro.com>
diff --git a/dmi.c b/dmi.c
index ca75461..d165e9f 100644
--- a/dmi.c
+++ b/dmi.c
@@ -79,8 +79,8 @@
 			printf_debug("DMI pipe open error\n");
 			goto out_free;
 		}
-		fgets(answerbuf, DMI_MAX_ANSWER_LEN, dmidecode_pipe);
-		if (ferror(dmidecode_pipe))
+		if (!fgets(answerbuf, DMI_MAX_ANSWER_LEN, dmidecode_pipe) &&
+		    ferror(dmidecode_pipe))
 		{
 			printf_debug("DMI pipe read error\n");
 			pclose(dmidecode_pipe);