Fix an invalid typecasting

Fix an invalid typecasting

entry->num_of_strings is a uint16_t. Casting it with

(int *)&entry->num_of_strings

is wrong, because it gives add_string_to_array the illusion that the object
"num" points to is an int, which it is not.

In case we are running on a machine where "int" is 32 or 64 bits long, what
happens with that cast? "add_string_to_array" interprets the byte field that
starts where "num_of_strings" starts as an int. Under very particular
circumstances this might work in a limited number of cases: When the byte order
of an int is such that the lower order bits of the int are stored first, the
subsequent bytes which do not belong to the uint16_t anymore happen to be 0 and
the result of the increment still fits into the first 2 bytes of that int, i.e.
the result is < 65536.

The correct solution to this problem is to use the implicit type conversion
that happens when an assignment is done.

BTW, this bug is found if you compile with -O3 -Wall, it shows up as a warning:

rpc_server/srv_eventlog_lib.c:574: warning: dereferencing type-punned pointer
	will break strict-aliasing rules

Thanks,

Volker