external/openssh: update to 6.8p1.

In preparation for some updates to external/openssh to make it work with
BoringSSL, this change updates the code to a recent version. The current
version (5.9p1) is coming up on four years old now.

  * Confirmed that f5c67b478bef9992de9e9ec91ce10af4f6205e0d matches
    OpenSSH 5.9p1 exactly (save for the removal of the scard
    subdirectory).

  * Downloaded openssh-6.8p1.tar.gz (SHA256:
    3ff64ce73ee124480b5bf767b9830d7d3c03bbcb6abe716b78f0192c37ce160e)
    and verified with PGP signature. (I've verified Damien's key in
    person previously.)

  * Applied changes between f5c67b478bef9992de9e9ec91ce10af4f6205e0d and
    OpenSSH 5.9p1 to 6.8p1 and updated the build as best I can. The
    ugliest change is probably the duplication of umac.c to umac128.c
    because Android conditionally compiles that file twice. See the
    comment in those files.

Change-Id: I63cb07a8118afb5a377f116087a0882914cea486
diff --git a/buildpkg.sh.in b/buildpkg.sh.in
index 4de9d42..4b842b3 100644
--- a/buildpkg.sh.in
+++ b/buildpkg.sh.in
@@ -337,17 +337,17 @@
 else
 	if [ "\${USE_SYM_LINKS}" = yes ]
 	then
-		[ "$RCS_D" = yes ]  &&  \
+		[ "$RCS_D" = yes ]  &&  \\
 	installf ${PKGNAME} \${PKG_INSTALL_ROOT}$TEST_DIR/etc/rcS.d/${SYSVINITSTOPT}${SYSVINIT_NAME}=../init.d/${SYSVINIT_NAME} s
 		installf ${PKGNAME} \${PKG_INSTALL_ROOT}$TEST_DIR/etc/rc0.d/${SYSVINITSTOPT}${SYSVINIT_NAME}=../init.d/${SYSVINIT_NAME} s
-		[ "$RC1_D" = no ]  ||  \
+		[ "$RC1_D" = no ]  ||  \\
 		installf ${PKGNAME} \${PKG_INSTALL_ROOT}$TEST_DIR/etc/rc1.d/${SYSVINITSTOPT}${SYSVINIT_NAME}=../init.d/${SYSVINIT_NAME} s
 		installf ${PKGNAME} \${PKG_INSTALL_ROOT}$TEST_DIR/etc/rc2.d/${SYSVINITSTART}${SYSVINIT_NAME}=../init.d/${SYSVINIT_NAME} s
 	else
-		[ "$RCS_D" = yes ]  &&  \
+		[ "$RCS_D" = yes ]  &&  \\
 	installf ${PKGNAME} \${PKG_INSTALL_ROOT}$TEST_DIR/etc/rcS.d/${SYSVINITSTOPT}${SYSVINIT_NAME}=\${PKG_INSTALL_ROOT}$TEST_DIR/etc/init.d/${SYSVINIT_NAME} l
 		installf ${PKGNAME} \${PKG_INSTALL_ROOT}$TEST_DIR/etc/rc0.d/${SYSVINITSTOPT}${SYSVINIT_NAME}=\${PKG_INSTALL_ROOT}$TEST_DIR/etc/init.d/${SYSVINIT_NAME} l
-		[ "$RC1_D" = no ]  ||  \
+		[ "$RC1_D" = no ]  ||  \\
 		installf ${PKGNAME} \${PKG_INSTALL_ROOT}$TEST_DIR/etc/rc1.d/${SYSVINITSTOPT}${SYSVINIT_NAME}=\${PKG_INSTALL_ROOT}$TEST_DIR/etc/init.d/${SYSVINIT_NAME} l
 		installf ${PKGNAME} \${PKG_INSTALL_ROOT}$TEST_DIR/etc/rc2.d/${SYSVINITSTART}${SYSVINIT_NAME}=\${PKG_INSTALL_ROOT}$TEST_DIR/etc/init.d/${SYSVINIT_NAME} l
 	fi
@@ -538,10 +538,10 @@
 PRE_INS_STOP=no
 POST_INS_START=no
 # determine if should restart the daemon
-if [ -s ${piddir}/sshd.pid  ] && \
+if [ -s ${piddir}/sshd.pid  ] && \\
     /usr/bin/svcs -H $OPENSSH_FMRI 2>&1 | egrep "^online" > /dev/null 2>&1
 then
-	ans=\`ckyorn -d n \
+	ans=\`ckyorn -d n \\
 -p "Should the running sshd daemon be restarted? ${DEF_MSG}"\` || exit \$?
 	case \$ans in
 		[y,Y]*)	PRE_INS_STOP=yes
@@ -552,7 +552,7 @@
 else
 
 # determine if we should start sshd
-	ans=\`ckyorn -d n \
+	ans=\`ckyorn -d n \\
 -p "Start the sshd daemon after installing this package? ${DEF_MSG}"\` || exit \$?
 	case \$ans in
 		[y,Y]*)	POST_INS_START=yes ;;
@@ -573,7 +573,7 @@
 PRE_INS_STOP=no
 POST_INS_START=no
 # Use symbolic links?
-ans=\`ckyorn -d n \
+ans=\`ckyorn -d n \\
 -p "Do you want symbolic links for the start/stop scripts? ${DEF_MSG}"\` || exit \$?
 case \$ans in
 	[y,Y]*)	USE_SYM_LINKS=yes ;;
@@ -582,7 +582,7 @@
 # determine if should restart the daemon
 if [ -s ${piddir}/sshd.pid  -a  -f ${TEST_DIR}/etc/init.d/${SYSVINIT_NAME} ]
 then
-	ans=\`ckyorn -d n \
+	ans=\`ckyorn -d n \\
 -p "Should the running sshd daemon be restarted? ${DEF_MSG}"\` || exit \$?
 	case \$ans in
 		[y,Y]*)	PRE_INS_STOP=yes
@@ -593,7 +593,7 @@
 else
 
 # determine if we should start sshd
-	ans=\`ckyorn -d n \
+	ans=\`ckyorn -d n \\
 -p "Start the sshd daemon after installing this package? ${DEF_MSG}"\` || exit \$?
 	case \$ans in
 		[y,Y]*)	POST_INS_START=yes ;;