Catch the error on set_value call

Sometimes the adcsensor crashes with the below error:
terminate called after throwing an instance of 'std::system_error'
  what():  error setting GPIO line values: Operation not permitted
Aborted (core dumped)

Catch such error to prevent service from crash.

Tested:
Change the threshold values on ADC sensor P3VBAT,
No such crash error

Signed-off-by: Yong Li <yong.b.li@linux.intel.com>
Change-Id: I05bebb792fc40f458033decd1cca3508af5b770c
diff --git a/include/ADCSensor.hpp b/include/ADCSensor.hpp
index dfd8713..e1f1330 100644
--- a/include/ADCSensor.hpp
+++ b/include/ADCSensor.hpp
@@ -42,7 +42,14 @@
     {
         if (line)
         {
-            line.set_value(value);
+            try
+            {
+                line.set_value(value);
+            }
+            catch (std::system_error& exc)
+            {
+                std::cerr << "Error set_value: " << exc.what() << "\n";
+            }
         }
     }