fix: oscap-ssh: instead of expr/let, use (( )) form

Handle options conversions up to 2nd last arg as last is input and is
handled next.

(( ..., 1 )) ensures return value is ok.
arr[-1] is last element

From shellcheck:

In utils/oscap-ssh line 217:
for i in $(seq 0 `expr $# - 1`); do
                 ^-----------^ SC2046: Quote this to prevent word splitting.
                 ^-----------^ SC2006: Use $(...) notation instead of legacy backticked `...`.
                  ^--^ SC2003: expr is antiquated. Consider rewriting this using $((..)), ${} or [[ ]].

Did you mean:
for i in $(seq 0 $(expr $# - 1)); do

In utils/oscap-ssh line 218:
    let j=i+1
    ^-------^ SC2219: Instead of 'let expr', prefer (( expr )) .

In utils/oscap-ssh line 267:
    LOCAL_CONTENT_PATH="${oscap_args[`expr $# - 1`]}"
                                     ^-----------^ SC2006: Use $(...) notation instead of legacy backticked `...`.
                                      ^--^ SC2003: expr is antiquated. Consider rewriting this using $((..)), ${} or [[ ]].

Did you mean:
    LOCAL_CONTENT_PATH="${oscap_args[$(expr $# - 1)]}"

In utils/oscap-ssh line 268:
    oscap_args[`expr $# - 1`]="$REMOTE_TEMP_DIR/input.xml"
               ^-----------^ SC2006: Use $(...) notation instead of legacy backticked `...`.
                ^--^ SC2003: expr is antiquated. Consider rewriting this using $((..)), ${} or [[ ]].

Did you mean:
    oscap_args[$(expr $# - 1)]="$REMOTE_TEMP_DIR/input.xml"

Author: maage

utils/oscap-ssh

@@ -214,8 +214,8 @@ TARGET_SYSCHAR=""
 OVAL_RESULTS=""
 
 # We have to rewrite various paths to a remote temp dir
-for i in $(seq 0 `expr $# - 1`); do
-    let j=i+1
+for (( i=0; i < $#-1; i++ )); do
+    (( j=i+1, 1 ))
 
     case "${oscap_args[i]}" in
     ("--tailoring-file")
@@ -264,8 +264,8 @@ done
 
 if [ "$1" != "--v" ] && [ "$1" != "--version" ] && [ "$1" != "-h" ] && [ "$1" != "--help" ]; then
     # Last argument should be the content path
-    LOCAL_CONTENT_PATH="${oscap_args[`expr $# - 1`]}"
-    oscap_args[`expr $# - 1`]="$REMOTE_TEMP_DIR/input.xml"
+    LOCAL_CONTENT_PATH="${oscap_args[-1]}"
+    oscap_args[-1]="$REMOTE_TEMP_DIR/input.xml"
 fi
 
 [ "$LOCAL_CONTENT_PATH" == "" ] || [ -f "$LOCAL_CONTENT_PATH" ] || die "Expected the last argument to be an input file, '$LOCAL_CONTENT_PATH' isn't a valid file path or the file doesn't exist!"