eet_cipher: Fix initialization of opened variable

eet_cipher: Fix initialization of opened variable

In the error case we 'goto' the error path directly without passing
through the declaration and initialization of the variable.

This doesn't work so move the declaration/initialization to the start.
See this example (compile with -Wall for the warning):

-----
 #include <stdio.h>

 int main(void)
 {
   goto bar;

   int i = 15;

 bar:
   printf("Foo: %i\n", i);

   return 0;
 }
----

Signed-off-by: Daniel Willmann <d.willmann@samsung.com>