strmap: make callers of strmap_remove() to call it in void context

strmap: make callers of strmap_remove() to call it in void context

Two "static inline" functions, both of which return void, call
strmap_remove() and tries to return the value it returns as their
return value, which is just bogus, as strmap_remove() returns void
itself.  Call it in the void context and fall-thru the control to
the end instead.

Reported-by: Randall S. Becker <rsbecker@nexbridge.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>