env: common: accept flags on reset to default env

The function set_default_env() sets the hashtable flags for import_r().
Formally set_default_env() doesn't accept flags from its callers. In
practice the caller can (un)set the H_INTERACTIVE flag, but it has to be
done using the first character of the function's string argument. Other
flags like H_FORCE can't be set by the caller.

Change the function to accept flags argument. The benefits are:
1. The caller will have to explicitly set the H_INTERACTIVE flag,
   instead of un-setting it using a special char in a string.
2. Add the ability to propagate flags from the caller to himport(),
   especially the H_FORCE flag from do_env_default() in nvedit.c that
   currently gets ignored for "env default -a -f" commands.
3. Flags and messages will not be coupled together. A caller will be
   able to set flags without passing a string and vice versa.

Please note:
The propagation of H_FORCE from do_env_default() does not introduce any
functional changes, because currently himport_r() is set to destroy the
old environment regardless if H_FORCE flag is set or not. More changes
are needed to utilize the propagation of H_FORCE.

Signed-off-by: Yaniv Levinsky <yaniv.levinsky@compulab.co.il>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>
diff --git a/env/ubi.c b/env/ubi.c
index d28247b..eb2346f 100644
--- a/env/ubi.c
+++ b/env/ubi.c
@@ -114,7 +114,7 @@
 	if (ubi_part(CONFIG_ENV_UBI_PART, NULL)) {
 		printf("\n** Cannot find mtd partition \"%s\"\n",
 		       CONFIG_ENV_UBI_PART);
-		set_default_env(NULL);
+		set_default_env(NULL, 0);
 		return -EIO;
 	}
 
@@ -151,14 +151,14 @@
 	if (ubi_part(CONFIG_ENV_UBI_PART, NULL)) {
 		printf("\n** Cannot find mtd partition \"%s\"\n",
 		       CONFIG_ENV_UBI_PART);
-		set_default_env(NULL);
+		set_default_env(NULL, 0);
 		return -EIO;
 	}
 
 	if (ubi_volume_read(CONFIG_ENV_UBI_VOLUME, buf, CONFIG_ENV_SIZE)) {
 		printf("\n** Unable to read env from %s:%s **\n",
 		       CONFIG_ENV_UBI_PART, CONFIG_ENV_UBI_VOLUME);
-		set_default_env(NULL);
+		set_default_env(NULL, 0);
 		return -EIO;
 	}