Add dependency for hexdump

hexdump is used in common function generate_hex_string which is
used by nova and heat.  The current general dependencies do not
have this dependency covered, instead it is usually pulled in by
other implicit dependencies when a full devstack is built. In
cases where only a subset is built (like just Heat and keystone)
hexdump is missing.

Added unit tests for the generate_hex_string function.

Depends-On: Ib47d802a31a0f4c2a49daa7e6698e37c70a2365a
Change-Id: I77c8c2019fb8b8174cdfaed3e56ebf728f0732b7
Closes-Bug: #1558672
(cherry picked from commit d99c29032b)
(cherry picked from commit 603fc0c6ec)

files/debs/general

@@ -3,6 +3,7 @@ screen
 unzip
 wget
 psmisc
+bsdmainutils
 gcc
 g++
 git

files/rpms-suse/general

@@ -19,5 +19,6 @@ screen
 tar
 tcpdump
 unzip
+util-linux
 wget
 net-tools

files/rpms/general

@@ -19,6 +19,7 @@ screen
 tar
 tcpdump
 unzip
+util-linux
 wget
 which
 bc

tests/test_functions.sh

@@ -9,6 +9,22 @@ source $TOP/functions
 
 source $TOP/tests/unittest.sh
 
+echo "Testing generate_hex_string()"
+
+VAL=$(generate_hex_string 16)
+if [[ ${#VAL} -eq 32 ]]; then
+    passed "OK"
+else
+    failed "generate_hex_string 16 failed ${#VAL}"
+fi
+
+VAL=$(generate_hex_string 32)
+if [[ ${#VAL} -eq 64 ]]; then
+    passed "OK"
+else
+    failed "generate_hex_string 32 failed ${#VAL}"
+fi
+
 echo "Testing die_if_not_set()"
 
 bash -c "source $TOP/functions; X=`echo Y && true`; die_if_not_set $LINENO X 'not OK'"