Added support for quote commands before a transfer using SFTP and test

case 614.
Allow SFTP quote commands chmod, chown, chgrp to set a value of 0.

tests/data/Makefile.am

@@ -41,4 +41,4 @@ EXTRA_DIST = test1 test108 test117 test127 test20 test27 test34 test46	   \
  test603 test401 test402 test290 test291 test292 test293 test403 test404   \
  test405 test604 test605 test606 test607 test608 test609 test294 test295   \
  test296 test297 test298 test610 test611 test612 test406 test407 test408   \
- test409 test613
+ test409 test613 test614

tests/data/test614

@@ -0,0 +1,49 @@
+<testcase>
+<info>
+<keywords>
+SFTP
+pre-quote
+directory
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<datacheck>
+d?????????   N     U     U          N ???  N NN:NN .
+d?????????   N     U     U          N ???  N NN:NN ..
+d?????????   N     U     U          N ???  N NN:NN asubdir
+-r-?r-?r-?   1     U     U         37 Jan  1  2000 plainfile.txt
+-r-?r-?r-?   1     U     U         47 Dec 31  2000 rofile.txt
+</datacheck>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+sftp
+</server>
+<precheck>
+perl %SRCDIR/libtest/test613.pl prepare %PWD/log/test614.dir
+</precheck>
+ <name>
+SFTP pre-quote chmod
+ </name>
+ <command>
+--key curl_client_key --pubkey curl_client_key.pub -u %USER: -Q "chmod 444 %PWD/log/test614.dir/plainfile.txt" sftp://%HOSTIP:%SSHPORT%PWD/log/test614.dir/
+</command>
+<postcheck>
+perl %SRCDIR/libtest/test613.pl postprocess %PWD/log/test614.dir %PWD/log/curl614.out
+</postcheck>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<valgrind>
+disable
+</valgrind>
+</verify>
+</testcase>