VPP-498: Prepare vpp RPM packaging for use by downstream distros.

Change spec to add new macros to get rid of relative dir reference and
use vpp version. Store version string in .version to store metadata in
dist archive. New script to create dist archive.
Add dist and wipedist targets to Makefile for builds of source RPMs.

Change-Id: I7cf0164f0cb094ec70f3dc323ed7fa2ee82bd902
Signed-off-by: Thomas F Herbert <therbert@redhat.com>

build-root/scripts/version

@@ -1,8 +1,32 @@
 #!/bin/bash
 
-TAG=$(git describe | cut -d- -f1 | sed -e 's/^v//')
-ADD=$(git describe | cut -s -d- -f2)
-CMT=$(git describe --dirty --match 'v*'| cut -s -d- -f3,4)
+path=$( cd "$(dirname "${BASH_SOURCE}")" ; pwd -P )
+
+cd "$path"
+
+git rev-parse 2> /dev/null
+if [ $? == 0 ]; then
+    vstring=$(git describe)
+elif [ -f .version ]; then
+    vstring=$(cat .version)
+else
+    if [ -f ../rpm/*.gz ]; then
+        vstring=$(ls ../rpm/*.gz)
+    else
+        exit 1
+    fi
+fi
+
+TAG=$(echo ${vstring} | cut -d- -f1 | sed -e 's/^v//')
+ADD=$(echo ${vstring} | cut -s -d- -f2)
+
+git rev-parse 2> /dev/null
+if [ $? == 0 ]; then
+    CMT=$(git describe --dirty --match 'v*'| cut -s -d- -f3,4)
+else
+    CMT=$(echo ${vstring} | cut -s -d- -f3,4)
+fi
+CMTR=$(echo $CMT | sed 's/-/_/')
 
 if [ -n "${BUILD_NUMBER}" ]; then
        BLD="~b${BUILD_NUMBER}"
@@ -15,13 +39,16 @@ fi
 
 if [ "$1" = "rpm-release" ]; then
   [ -z "${ADD}" ] && echo release && exit
-  CMT=$(git describe --dirty --match 'v*'| cut -s -d- -f3,4 | sed 's/-/_/')
-  echo ${ADD}${CMT:+~${CMT}}${BLD}
+  echo ${ADD}${CMTR:+~${CMTR}}${BLD}
   exit
 fi
 
-if [ -n "${ADD}" ]; then
-  echo ${TAG}-${ADD}${CMT:+~${CMT}}${BLD}
-else
-  echo ${TAG}
+  if [ -n "${ADD}" ]; then
+    if [ "$1" = "rpm-string" ]; then
+      echo ${TAG}-${ADD}${CMTR:+~${CMTR}}${BLD}
+    else
+      echo ${TAG}-${ADD}${CMT:+~${CMT}}${BLD}
+    fi
+  else
+    echo ${TAG}
 fi