collectd: prepare ubi plugin for percent calculation

This patche change prepares the ubi plugin to add the bad block evaluation in
percent.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

utils/collectd/patches/934-ubi-prepare-read-for-percent.patch

@@ -0,0 +1,66 @@
+--- a/src/ubi.c
++++ b/src/ubi.c
+@@ -84,9 +84,8 @@ static void ubi_submit(const char *dev_n
+   plugin_dispatch_values(&vl);
+ } /* void ubi_submit */
+ 
+-static int ubi_read_dev_attr(const char *dev_name, const char *attr) {
++static int ubi_read_dev_attr(const char *dev_name, const char *attr, int *value) {
+   FILE *f;
+-  int val;
+   char
+       str[sizeof(SYS_PATH) + strlen(dev_name) + sizeof("/") + strlen(attr) + 1];
+   int n;
+@@ -98,7 +97,7 @@ static int ubi_read_dev_attr(const char
+     return -1;
+   }
+ 
+-  n = fscanf(f, "%d", &val);
++  n = fscanf(f, "%d", value);
+   fclose(f);
+ 
+   if (n != 1) {
+@@ -106,17 +105,39 @@ static int ubi_read_dev_attr(const char
+     return -1;
+   }
+ 
+-  ubi_submit(dev_name, attr, (gauge_t)val);
+-
+   return 0;
+ } /* int ubi_read_dev_attr */
+ 
+ static inline int ubi_read_dev_bad_count(const char *dev_name) {
+-  return ubi_read_dev_attr(dev_name, DEV_BAD_COUNT);
++  int ret;
++  int value;
++
++  ret = ubi_read_dev_attr(dev_name, DEV_BAD_COUNT, &value);
++
++  if (ret != 0) {
++    ERROR(PLUGIN_NAME " : Unable to read bat_peb_count");
++    return -1;
++  }
++
++  ubi_submit(dev_name, DEV_BAD_COUNT, (gauge_t)value);
++
++  return 0;
+ } /* int ubi_read_dev_bad_count */
+ 
+ static inline int ubi_read_max_ec(const char *dev_name) {
+-  return ubi_read_dev_attr(dev_name, MAXIMUM_ERASE);
++  int ret;
++  int value;
++
++  ret = ubi_read_dev_attr(dev_name, MAXIMUM_ERASE, &value);
++
++  if (ret != 0) {
++    ERROR(PLUGIN_NAME " : Unable to read max_ec");
++    return -1;
++  }
++
++  ubi_submit(dev_name, MAXIMUM_ERASE, (gauge_t)value);
++
++  return 0;
+ } /* int ubi_read_max_ec */
+ 
+ static int ubi_read(void) {