Improve the UX around sample config generation

This commit just adds some documentation around using the sample config
generator. It also adds a wrapper script that sets the env variable for
running the oslo generator script with tempest.

Change-Id: I860b17defeeb85174e68b1e8b046b0e43c30683b
diff --git a/tools/config/check_uptodate.sh b/tools/config/check_uptodate.sh
index 9882ab6..45c8629 100755
--- a/tools/config/check_uptodate.sh
+++ b/tools/config/check_uptodate.sh
@@ -5,6 +5,6 @@
 if ! diff $TEMPDIR/$CFGFILE etc/$CFGFILE
 then
     echo "E: tempest.conf.sample is not up to date, please run:"
-    echo "MODULEPATH=tempest.common.generate_sample_tempest tools/config/generate_sample.sh"
+    echo "tools/generate_sample.sh"
     exit 42
 fi
diff --git a/tools/generate_sample.sh b/tools/generate_sample.sh
new file mode 100755
index 0000000..9b312c9
--- /dev/null
+++ b/tools/generate_sample.sh
@@ -0,0 +1,2 @@
+#!/bin/sh
+MODULEPATH=tempest.common.generate_sample_tempest tools/config/generate_sample.sh $@