harness: Make the harness more Windows friendly.

Msys automatically transforms paths for executed commands, but it is
unable to do that for paths in the config files.  This updates all of
the paths in the config files to use relative paths instead so they work
with the various processes.

It also use the posix compliant shebang for locating bash, adds a new
variable to control whether or not the profiling ports are enabled, and
disables postgres by default.

harness.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # Copyright (c) 2020 The Decred developers
 # Use of this source code is governed by an ISC
@@ -30,8 +30,12 @@ PAYMENT_METHOD="pplns"
 LAST_N_PERIOD=5m
 GUI_DIR="${HARNESS_ROOT}/gui"
 
+# Enabling profiling uses a lot more ports that might conflict with other Decred
+# software.  Set to 1 to enable.  Leave blank to disable.
+ENABLE_PROFILING=
+
 # Using postgres requires the DB specified below to already exist.
-USE_POSTGRES=1
+USE_POSTGRES=0
 POSTGRES_HOST=127.0.0.1
 POSTGRES_PORT=5432
 POSTGRES_USER=dcrpooluser
@@ -101,31 +105,31 @@ user=m$i
 address=${CLIENT_ADDRS[$i]}
 pool=127.0.0.1:5550
 maxprocs=$MINER_MAX_PROCS
-profile=$PROFILE_PORT
+profile=${ENABLE_PROFILING-$PROFILE_PORT}
 EOF
 done
 
 cat > "${HARNESS_ROOT}/master/dcrmctl.conf" <<EOF
 rpcuser=${RPC_USER}
 rpcpass=${RPC_PASS}
-rpccert=${HARNESS_ROOT}/master/rpc.cert
+rpccert=./rpc.cert
 rpcserver=127.0.0.1:19556
 EOF
 
 cat > "${HARNESS_ROOT}/vnode/dcrvctl.conf" <<EOF
 rpcuser=${RPC_USER}
 rpcpass=${RPC_PASS}
-rpccert=${HARNESS_ROOT}/vnode/rpc.cert
+rpccert=./rpc.cert
 rpcserver=127.0.0.1:19560
 EOF
 
 cat > "${HARNESS_ROOT}/pool/pool.conf" <<EOF
 rpcuser=${RPC_USER}
 rpcpass=${RPC_PASS}
 dcrdrpchost=127.0.0.1:19556
-dcrdrpccert=${HARNESS_ROOT}/master/rpc.cert
+dcrdrpccert=../master/rpc.cert
 walletgrpchost=127.0.0.1:19558
-walletrpccert=${HARNESS_ROOT}/mwallet/rpc.cert
+walletrpccert=../mwallet/rpc.cert
 debuglevel=trace
 maxgentime=${MAX_GEN_TIME}
 solopool=${SOLO_POOL}
@@ -135,9 +139,9 @@ poolfeeaddrs=${PFEE_ADDR}
 paymentmethod=${PAYMENT_METHOD}
 lastnperiod=${LAST_N_PERIOD}
 adminpass=${ADMIN_PASS}
-guidir=${GUI_DIR}
+guidir=../gui
 designation=${TMUX_SESSION}
-profile=6060
+profile=${ENABLE_PROFILING-6060}
 postgres=${USE_POSTGRES}
 postgreshost=${POSTGRES_HOST}
 postgresport=${POSTGRES_PORT}
@@ -149,24 +153,24 @@ EOF
 cat > "${HARNESS_ROOT}/mwallet/dcrmwctl.conf" <<EOF
 rpcuser=${RPC_USER}
 rpcpass=${RPC_PASS}
-rpccert=${HARNESS_ROOT}/mwallet/rpc.cert
+rpccert=./rpc.cert
 rpcserver=127.0.0.1:19557
 EOF
 
 cat > "${HARNESS_ROOT}/vwallet/dcrvwctl.conf" <<EOF
 rpcuser=${RPC_USER}
 rpcpass=${RPC_PASS}
-rpccert=${HARNESS_ROOT}/vwallet/rpc.cert
+rpccert=./rpc.cert
 rpcserver=127.0.0.1:19562
 EOF
 
 cat > "${HARNESS_ROOT}/mwallet/mwallet.conf" <<EOF
 username=${RPC_USER}
 password=${RPC_PASS}
-cafile=${HARNESS_ROOT}/master/rpc.cert
-clientcafile=${HARNESS_ROOT}/pool/wallet.cert
-logdir=${HARNESS_ROOT}/mwallet/log
-appdata=${HARNESS_ROOT}/mwallet
+cafile=../master/rpc.cert
+clientcafile=../pool/wallet.cert
+logdir=./logs
+appdata=../mwallet
 simnet=1
 pass=${WALLET_PASS}
 accountgaplimit=25
@@ -175,9 +179,9 @@ EOF
 cat > "${HARNESS_ROOT}/vwallet/vwallet.conf" <<EOF
 username=${RPC_USER}
 password=${RPC_PASS}
-cafile=${HARNESS_ROOT}/vnode/rpc.cert
-logdir=${HARNESS_ROOT}/vwallet/log
-appdata=${HARNESS_ROOT}/vwallet
+cafile=../vnode/rpc.cert
+logdir=./logs
+appdata=../vwallet
 simnet=1
 enablevoting=1
 enableticketbuyer=1