cmd: nvedit: propagate envflag to set_default_vars

The env_flag in do_env_default() doesn't get propagated and therefore
gets ignored by himport_r(). This breaks to ability to "forcibly" reset
variables to their default values using the environment command.

Scenario example of the problem:
	# setenv kernel uImage
	# setenv .flags kernel:so
	# env default -f kernel
	## Error: Can't overwrite "kernel"
	himport_r: can't insert "kernel=zImage" into hash table

Change the call path so it will pass the flag correctly.

Signed-off-by: Yaniv Levinsky <yaniv.levinsky@compulab.co.il>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>
diff --git a/include/environment.h b/include/environment.h
index 70b7eda..2fe1f3e 100644
--- a/include/environment.h
+++ b/include/environment.h
@@ -275,7 +275,7 @@
 void set_default_env(const char *s);
 
 /* [re]set individual variables to their value in the default environment */
-int set_default_vars(int nvars, char * const vars[]);
+int set_default_vars(int nvars, char * const vars[], int flags);
 
 /* Import from binary representation into hash table */
 int env_import(const char *buf, int check);