fix "scripts: zephyr_flash_debug: flash like openocd.sh"

All commands need to have quotation marks stripped.

Fixes: bee6f9e73 ("scripts: zephyr_flash_debug: flash like openocd.sh")
Signed-off-by: Marti Bolivar <marti.bolivar@linaro.org>
diff --git a/scripts/support/zephyr_flash_debug.py b/scripts/support/zephyr_flash_debug.py
index 55564ed..691a220 100755
--- a/scripts/support/zephyr_flash_debug.py
+++ b/scripts/support/zephyr_flash_debug.py
@@ -587,7 +587,11 @@
         openocd = os.environ.get('OPENOCD', 'openocd')
         default_path = os.environ.get('OPENOCD_DEFAULT_PATH', None)
         pre_cmd = os.environ.get('OPENOCD_PRE_CMD', None)
+        if pre_cmd is not None:
+            pre_cmd = pre_cmd.strip('"')
         post_cmd = os.environ.get('OPENOCD_POST_CMD', None)
+        if post_cmd is not None:
+            post_cmd = post_cmd.strip('"')
 
         return OpenOcdBinaryFlasher(bin_name, zephyr_base, arch, board_name,
                                     load_cmd, verify_cmd, openocd=openocd,