phosphor-debug-collector: Fix invalied escape sequence

There is a warning message in the phosphor-debug-collector repo when
using bitbake to build image-bmc:
DeprecationWarning: invalid escape sequence \W
   config_values = re.split('\W+', parse_value, 1)

The reason is that `\W` is regarded as an escaped character,
add `r` to fix it.

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: I59836e7df9a73a01d47cd03e916f0ab1b8c2d716
diff --git a/meta-phosphor/recipes-phosphor/dump/phosphor-debug-collector_git.bb b/meta-phosphor/recipes-phosphor/dump/phosphor-debug-collector_git.bb
index 2b7372a2..8d40965 100644
--- a/meta-phosphor/recipes-phosphor/dump/phosphor-debug-collector_git.bb
+++ b/meta-phosphor/recipes-phosphor/dump/phosphor-debug-collector_git.bb
@@ -147,7 +147,7 @@
             bb.warn("Invalid format for config value =%s" % line)
             continue
         parse_value = revalue.group(0)
-        config_values = re.split('\W+', parse_value, 1)
+        config_values = re.split(r'\W+', parse_value, 1)
         if(len(config_values) != 2):
             bb.warn("Invalid config value=%s" % parse_value)
             break;