contrib/build-wine/unsign.sh: small improvements/fixes

- follow-up prev: CONTRIB was not defined
- rm folder signed/stripped if already exists (otherwise script early-exited silently)
- quote paths to guard against whitespace shenanigans

contrib/build-wine/unsign.sh

@@ -1,4 +1,7 @@
 #!/bin/bash
+
+PROJECT_ROOT="$(dirname "$(readlink -e "$0")")/../.."
+CONTRIB="$PROJECT_ROOT/contrib"
 here=$(dirname "$0")
 test -n "$here" -a -d "$here" || exit
 cd $here
@@ -11,6 +14,7 @@ fi
 # exit if command fails
 set -e
 
+rm -rf signed/stripped
 mkdir -p signed >/dev/null 2>&1
 mkdir -p signed/stripped >/dev/null 2>&1
 
@@ -20,18 +24,18 @@ echo "Found $(ls dist/*.exe | wc -w) files to verify."
 
 for mine in $(ls dist/*.exe); do
     echo "---------------"
-    f=$(basename $mine)
+    f="$(basename $mine)"
-    if test -f signed/$f; then
+    if test -f "signed/$f"; then
         echo "Found file at signed/$f"
     else
         echo "Downloading https://download.electrum.org/$version/$f"
-        wget -q https://download.electrum.org/$version/$f -O signed/$f
+        wget -q "https://download.electrum.org/$version/$f" -O "signed/$f"
     fi
     out="signed/stripped/$f"
     # Remove PE signature from signed binary
-    osslsigncode remove-signature -in signed/$f -out $out > /dev/null 2>&1
+    osslsigncode remove-signature -in "signed/$f" -out "$out" > /dev/null 2>&1
-    chmod +x $out
+    chmod +x "$out"
-    if cmp -s $out $mine; then
+    if cmp -s "$out" "$mine"; then
         echo "Success: $f"
         #gpg --sign --armor --detach signed/$f
     else