extract_utils: extract(): rename FROM variable to SPEC_DST_FILE

* This is a cleanup patch.

Change-Id: I308b0478484ccf9a594078825731606fce5f5507
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>

build/tools/extract_utils.sh

@@ -982,7 +982,7 @@ function extract() {
 
     for (( i=1; i<COUNT+1; i++ )); do
 
-        local FROM=$(target_file "${FILELIST[$i-1]}")
+        local SPEC_DST_FILE=$(target_file "${FILELIST[$i-1]}")
         local ARGS=$(target_args "${FILELIST[$i-1]}")
         local FILE=$(src_file "${FILELIST[$i-1]}")
         local OUTPUT_DIR="$OUTPUT_ROOT"
@@ -990,11 +990,11 @@ function extract() {
         local TARGET=
 
         if [ "$ARGS" = "rootfs" ]; then
-            TARGET="$FROM"
+            TARGET="${SPEC_DST_FILE}"
             OUTPUT_DIR="$OUTPUT_DIR/rootfs"
             TMP_DIR="$TMP_DIR/rootfs"
         else
-            TARGET="system/$FROM"
+            TARGET="system/${SPEC_DST_FILE}"
             FILE="system/$FILE"
         fi
 
@@ -1004,11 +1004,11 @@ function extract() {
             printf '  - %s \n' "/$TARGET"
         fi
 
-        local DIR=$(dirname "$FROM")
+        local DIR=$(dirname "${SPEC_DST_FILE}")
         if [ ! -d "$OUTPUT_DIR/$DIR" ]; then
             mkdir -p "$OUTPUT_DIR/$DIR"
         fi
-        local DEST="$OUTPUT_DIR/$FROM"
+        local DEST="$OUTPUT_DIR/${SPEC_DST_FILE}"
 
         # Check pinned files
         local HASH="${HASHLIST[$i-1]}"
@@ -1017,7 +1017,7 @@ function extract() {
             if [ -f "$DEST" ]; then
                 local PINNED="$DEST"
             else
-                local PINNED="$TMP_DIR/$FROM"
+                local PINNED="$TMP_DIR/${SPEC_DST_FILE}"
             fi
             if [ -f "$PINNED" ]; then
                 if [ "$(uname)" == "Darwin" ]; then