build: touch files when extracting rpm tarballs

Type: fix

- Long story short, intermittently centos jobs have been
  failing with clock skew issues. When someone commits a
  patch on a machine with the date ahead of UTC, then clock
  skew will be encountered when extracting the RPM source
  tarball. See [0] and [1] for details.

- Replace 'make bootstrap' with 'make install-dep' in
  RPM package build specfile.

[0] https://unix.stackexchange.com/questions/164807/does-git-archive-use-the-wrong-file-timestamp
[1] https://git.fd.io/vpp/tree/Makefile#n380

Change-Id: Iebfb9eb2e26c1f2e4488e871da86d0c60b9f4048
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>

extras/rpm/vpp.spec

@@ -168,7 +168,10 @@ Requires(post): python3-policycoreutils
 This package contains a tailored VPP SELinux policy
 
 %prep
-%setup -q -n %{name}-%{_version}
+%setup -q -c -T -n %{name}-%{_version}
+cd ..
+unxz --stdout ./SOURCES/%{name}-%{_version}-%{_release}.tar.xz | tar --extract --touch
+cd -
 
 %pre
 # Add the vpp group
@@ -179,7 +182,7 @@ groupadd -f -r vpp
 . /opt/rh/devtoolset-9/enable
 %endif
 %if %{with aesni}
-    make bootstrap
+    make install-dep
     make -C build-root PLATFORM=vpp TAG=%{_vpp_tag} install-packages
 %else
     make bootstrap AESNI=n