Remove extraneous semicolon from mcrouter/lib/fbi/counting_sem.cpp

Summary:
Extraneous semicolons are a code smell and can mask more serious problems. `-Wextra-semi-stmt` finds them.

This diff removes an extraneous semicolon or adjusts a macro so that a semicolon is required after the macro (making it look like a standard function).

This file is drawn from a heavy-hitting list, so fixing this problem will allow *many* other files to take advantage of the safety `-Wextra-semi-stmt` offers.

This should be a low-risk diff: if it compiles, it works.

Reviewed By: meyering

Differential Revision: D51631114

fbshipit-source-id: 0f2aa3cfc77283d89c8444231b3a9de421a10850

mcrouter/lib/fbi/counting_sem.cpp

@@ -20,11 +20,10 @@
 #include "mcrouter/lib/fbi/util.h"
 
 #define fbi_futex_wait(p, val) \
-  syscall(                     \
-      SYS_futex, (p), FUTEX_WAIT | FUTEX_PRIVATE_FLAG, (val), NULL, NULL, 0);
+  syscall(SYS_futex, (p), FUTEX_WAIT | FUTEX_PRIVATE_FLAG, (val), NULL, NULL, 0)
 
 #define fbi_futex_wake(p, n) \
-  syscall(SYS_futex, (p), FUTEX_WAKE | FUTEX_PRIVATE_FLAG, (n), NULL, NULL, 0);
+  syscall(SYS_futex, (p), FUTEX_WAKE | FUTEX_PRIVATE_FLAG, (n), NULL, NULL, 0)
 
 void counting_sem_init(counting_sem_t* sem, int32_t val) {
   sem->cnt.store(std::max(val, 0), std::memory_order_release);