su/su01_s1: fix mismatched double quotation marks

Expect code
* spawn su -c "/bin/su root -c \"echo \"\\\$TEST_LINE > $TEST_ENV_FILE\"\""
will be translated to
* spawn su -c /bin/su root -c "echo "\$TEST_LINE > /tmp/TEST_ENV_FILE_ROOT""
which actually should be
* spawn su -c /bin/su root -c "echo \$TEST_LINE > /tmp/TEST_ENV_FILE_ROOT"

Signed-off-by: DAN LI <li.dan@cn.fujitsu.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
diff --git a/testcases/commands/su/su01_s1 b/testcases/commands/su/su01_s1
index b50ebdf..fd2e485 100755
--- a/testcases/commands/su/su01_s1
+++ b/testcases/commands/su/su01_s1
@@ -145,7 +145,7 @@
 set i_have_env 0
 set test_env_var " "
 if { $i_am_root==1 } {
-	spawn su -c "/bin/su root -c \"echo \"\\\$TEST_LINE > $TEST_ENV_FILE\"\""
+	spawn su -c "/bin/su root -c \"echo \\\$TEST_LINE > $TEST_ENV_FILE\""
 	expect {
 		 "Password:" {
 			send "$PASSWD\r"