Don't use move in FOR_EACH_* macro

FOR_EACH_* macros are resolved to for loop. Using std::move inside it
will cause already moved object to be used when more than one observer
is registered. This patch fixes that.

This issue was already fixed in commit 61d967af, but was reintroduced in
a835780b.

Change-Id: I14b72371d369e4bdcaf3a6e30045bf8a1e8c3e1b