pjdfstest: Avoid needless use of expr

Sponsored by:	Klara, Inc.
Sponsored by:	NetApp, Inc.
Reviewed by:	markj
Differential Revision:	https://reviews.freebsd.org/D53443

contrib/pjdfstest/tests/ftruncate/12.t

@@ -22,7 +22,7 @@ EFBIG|EINVAL)
 	;;
 *)
 	echo "not ok ${ntest}"
-	ntest=`expr ${ntest} + 1`
+	ntest=$((ntest + 1))
 	;;
 esac
 expect 0 unlink ${n0}

contrib/pjdfstest/tests/link/05.t

@@ -27,7 +27,7 @@ while [ ${i} -le ${link_max} ]; do
 	if [ $? -ne 0 ]; then
 		break
 	fi
-	i=`expr $i + 1`
+	i=$((i + 1))
 done
 test_check $i -eq ${link_max}
 

contrib/pjdfstest/tests/link/15.t

@@ -26,7 +26,7 @@ while :; do
 	if [ $? -ne 0 ]; then
 		break
 	fi
-	i=`expr $i + 1`
+	i=$((i + 1))
 done
 expect ENOSPC link ${n0}/${n1} ${n0}/${n2}
 umount /dev/md${n}

contrib/pjdfstest/tests/mkdir/11.t

@@ -24,7 +24,7 @@ while :; do
 	if [ $? -ne 0 ]; then
 		break
 	fi
-	i=`expr $i + 1`
+	i=$((i + 1))
 done
 expect ENOSPC mkdir ${n0}/${n1} 0755
 umount /dev/md${n}

contrib/pjdfstest/tests/mkfifo/11.t

@@ -24,7 +24,7 @@ while :; do
 	if [ $? -ne 0 ]; then
 		break
 	fi
-	i=`expr $i + 1`
+	i=$((i + 1))
 done
 expect ENOSPC mkfifo ${n0}/${n1} 0644
 umount /dev/md${n}

contrib/pjdfstest/tests/open/19.t

@@ -24,7 +24,7 @@ while :; do
 	if [ $? -ne 0 ]; then
 		break
 	fi
-	i=`expr $i + 1`
+	i=$((i + 1))
 done
 expect ENOSPC open ${n0}/${i} O_RDONLY,O_CREAT 0644
 umount /dev/md${n}

contrib/pjdfstest/tests/symlink/11.t

@@ -24,7 +24,7 @@ while :; do
 	if [ $? -ne 0 ]; then
 		break
 	fi
-	i=`expr $i + 1`
+	i=$((i + 1))
 done
 expect ENOSPC symlink test ${n0}/${n1}
 umount /dev/md${n}

contrib/pjdfstest/tests/truncate/12.t

@@ -22,7 +22,7 @@ EFBIG|EINVAL)
 	;;
 *)
 	echo "not ok ${ntest}"
-	ntest=`expr ${ntest} + 1`
+	ntest=$((ntest + 1))
 	;;
 esac
 expect 0 unlink ${n0}