crashinfo: remove unused /usr/bin/gdb support

We have not had gdb 6.1 in the base system for some time; there is no
need to check for it.

Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D34478

usr.sbin/crashinfo/crashinfo.sh

@@ -44,19 +44,6 @@ cleanup()
 	[ -e $VMCORE ] && rm -f $VMCORE
 }
 
-# Find a gdb binary to use and save the value in GDB.
-find_gdb()
-{
-	local binary
-
-	for binary in /usr/local/bin/gdb /usr/libexec/gdb; do
-		if [ -x ${binary} ]; then
-			GDB=${binary}
-			return
-		fi
-	done
-}
-
 # Run a single gdb command against a kernel file in batch mode.
 # The kernel file is specified as the first argument and the command
 # is given in the remaining arguments.
@@ -66,11 +53,7 @@ gdb_command()
 
 	k=$1 ; shift
 
-	if [ ${GDB} = /usr/local/bin/gdb ]; then
-		${GDB} -batch -ex "$@" $k
-	else
-		echo -e "$@" | ${GDB} -x /dev/stdin -batch $k
-	fi
+	${GDB} -batch -ex "$@" $k
 }
 
 find_kernel()
@@ -173,8 +156,8 @@ if $BATCH; then
 	exec > $FILE 2>&1
 fi
 
-find_gdb
-if [ -z "$GDB" ]; then
+GDB=/usr/local/bin/gdb
+if [ ! -x "$GDB" ]; then
 	echo "Unable to find a kernel debugger."
 	echo "Please install the devel/gdb port or gdb package."
 	exit 1