Give negative-errno-on-fail a default

The 'negative-errno-on-fail' option was initially added when the
repo used autotools, and if not specified it defaulted to false.

When the repo was moved to meson a default value wasn't given, and
either at that point, or possibly when a new version of meson came
along, the option would get set to true if no explicit value was given.

Go back to the original behavior by specifying a default value of false
in meson.options.

Tested:
Before fix:

$ grep NEGATIVE build/config.h
  #define NEGATIVE_ERRNO_ON_FAIL 1

After:

$ grep NEGATIVE build/config.h
  #define NEGATIVE_ERRNO_ON_FAIL 0

Change-Id: Ib866edc4c774f72c3fdda596cb023280e8fe60f0
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/meson.options b/meson.options
index a424a8e..bf254eb 100644
--- a/meson.options
+++ b/meson.options
@@ -8,6 +8,7 @@
     'negative-errno-on-fail',
     description: 'Set sensor value to -errno on read failures.',
     type: 'boolean',
+    value: false,
 )
 option(
     'sensor-root',