sanitycheck: all output from flasher goes to logger.debug

Redirect all output from flasher to logger.debug().

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/scripts/sanitycheck b/scripts/sanitycheck
index a1288d1..c787478 100755
--- a/scripts/sanitycheck
+++ b/scripts/sanitycheck
@@ -790,8 +790,8 @@
             with subprocess.Popen(command, stderr=subprocess.PIPE, stdout=subprocess.PIPE) as proc:
                 try:
                     (stdout, stderr) = proc.communicate(timeout=30)
-                    if VERBOSE:
-                        print(stdout.decode())
+                    logger.debug(stdout.decode())
+
                     if proc.returncode != 0:
                         self.instance.reason = "Device issue (Flash?)"
                         with open(d_log, "w") as dlog_fp: