[R][Packaging] Fix pkg-config check in r/configure

[asfimport]

I installed the arrow R package version 4.0.0 from CRAN on an Intel Mac that does not have pkg-config installed, and I saw this in the installation log

./configure: line 81: pkg-config: command not found
./configure: line 82: pkg-config: command not found
./configure: line 83: pkg-config: command not found 

This is happening because of line 79 and 80:

pkg-config --version >/dev/null 2>&1
if [ "$ARROW_USE_PKG_CONFIG" != "false" ] && [ $? -eq 0 ]; then 

The first conditional on line 80 causes $? to be set to 0, so then the second conditional evaluates to true. Reverse the order of these two conditionals so that $? truly reflects whether pkg-config is installed.

Reporter: Ian Cook / @ianmcook
Assignee: Ian Cook / @ianmcook

PRs and other links:

• GitHub Pull Request #10198

_{Note: This issue was originally created as ARROW-12601. Please see the migration documentation for further details.}

[asfimport]

Ian Cook / @ianmcook:
Issue resolved by pull request 10198
#10198