Fix bsdgrep manpage clobbering grep(1) with default build options

The default build should install bsdgrep(1) and grep(1), with the latter
being gnugrep(1). WITH_BSD_GREP flips this situation such that we have
gnugrep(1) and grep(1), with the latter being bsdgrep(1).

Changes to start installing the zgrep script out of usr.bin/grep
inadvertently altered the default build such that grep(1) was being
installed, and it was bsdgrep(1). Correct the typo.

Reported by:	bcran
MFC after:	3 days

usr.bin/grep/Makefile

@@ -10,7 +10,7 @@ MAN1=	grep.1 zgrep.1
 .else
 PROG=	bsdgrep
 CLEANFILES+= bsdgrep.1
-MAN1=	grep.1 zgrep.1
+MAN1=	bsdgrep.1 zgrep.1
 
 bsdgrep.1: grep.1
 	${CP} ${.ALLSRC} ${.TARGET}