Fix placement of "static".

Various buildfarm critters were complaining about

pgbench.c:304:1: warning: 'static' is not at beginning of declaration [-Wold-style-declaration]

Evidently a thinko in 720b0ea.

Author: tglsfdc

src/bin/pgbench/pgbench.c

@@ -301,7 +301,7 @@ static const char *progname;
 
 #define WSEP '@'				/* weight separator */
 
-volatile static sig_atomic_t timer_exceeded = false;	/* flag from signal
+static volatile sig_atomic_t timer_exceeded = false;	/* flag from signal
 														 * handler */
 
 /*