script: Enable SC2001 rule for Gitian scripts

(cherry picked from commit bitcoin/bitcoin@17f81e9648)

contrib/gitian-descriptors/gitian-linux.yml

@@ -102,7 +102,8 @@ script: |
   CONFIG_SITE=${BASEPREFIX}/$(echo "${HOSTS}" | awk '{print $1;}')/share/config.site ./configure --prefix=/
   make dist
   SOURCEDIST=$(echo zcash-*.tar.gz)
-  DISTNAME=$(echo ${SOURCEDIST} | sed 's/.tar.*//')
+  DISTNAME=${SOURCEDIST/%.tar.gz}
+
   # Correct tar file order
   mkdir -p temp
   pushd temp

contrib/gitian-descriptors/gitian-osx.yml

@@ -97,7 +97,7 @@ script: |
   CONFIG_SITE=${BASEPREFIX}/$(echo "${HOSTS}" | awk '{print $1;}')/share/config.site ./configure --prefix=/
   make dist
   SOURCEDIST=$(echo bitcoin-*.tar.gz)
-  DISTNAME=$(echo ${SOURCEDIST} | sed 's/.tar.*//')
+  DISTNAME=${SOURCEDIST/%.tar.gz}
 
   # Correct tar file order
   mkdir -p temp

contrib/gitian-descriptors/gitian-win-signer.yml

@@ -33,6 +33,6 @@ script: |
   make
   find ${UNSIGNED_DIR} -name "*-unsigned.exe" | while read i; do
     INFILE="$(basename "${i}")"
-    OUTFILE="$(echo "${INFILE}" | sed s/-unsigned//)"
+    OUTFILE="${INFILE/%-unsigned}"
     ./osslsigncode attach-signature -in "${i}" -out "${OUTDIR}/${OUTFILE}" -sigin "${SIGDIR}/${INFILE}.pem"
   done

contrib/gitian-descriptors/gitian-win.yml

@@ -118,7 +118,8 @@ script: |
   CONFIG_SITE=${BASEPREFIX}/$(echo "${HOSTS}" | awk '{print $1;}')/share/config.site ./configure --prefix=/
   make dist
   SOURCEDIST=$(echo bitcoin-*.tar.gz)
-  DISTNAME=$(echo ${SOURCEDIST} | sed 's/.tar.*//')
+  DISTNAME=${SOURCEDIST/%.tar.gz}
+
   # Correct tar file order
   mkdir -p temp
   pushd temp

test/lint/lint-shell.sh

@@ -24,7 +24,6 @@ disabled=(
     SC2162 # read without -r will mangle backslashes.
 )
 disabled_gitian=(
-    SC2001 # See if you can use ${variable//search/replace} instead.
     SC2035 # Use ./*glob* or -- *glob* so names with dashes won't become options.
     SC2043 # This loop will only ever run once for a constant value. Did you perhaps mean to loop over dir/*, $var or $(cmd)?
     SC2094 # Make sure not to read and write the same file in the same pipeline.