auto/otel: Remove pkg-config check

@thresheek reported an issue trying to configure OTEL support on Amazon
Linux 2

  checking for OTEL requirements:
    - checking for rust compiler ... found
    - checking for cargo ... found
    - checking for OpenSSL library ... found
  Package openssl was not found in the pkg-config search path.
  Perhaps you should add the directory containing `openssl.pc'
  to the PKG_CONFIG_PATH environment variable
  No package 'openssl' found

We successfully built the test program with '-lssl -lcrypto', but then
tried to use 'pkg-config openssl --cflags --libs' to override
NXT_OTEL_LIBS.

On Amazon Linux2 there is no openssl.pc, they have a openssl11.pc.

Let's just remove the pkg-config check, if we get here, we have
successfully built with '-lssl -lcrypto', so just go with that (it also
matches what we do in auto/ssltls).

Closes: #1510
Signed-off-by: Andrew Clayton <[email protected]>

auto/otel

@@ -41,9 +41,7 @@ if [ $NXT_OTEL = YES ]; then
     fi
 
     NXT_OTEL_LIBS="-lssl -lcrypto"
-    if [ $(which pkg-config) ]; then
-        NXT_OTEL_LIBS="$(pkg-config openssl --cflags --libs)"
-    fi
+
     cat << END >> $NXT_AUTO_CONFIG_H
 
 #ifndef NXT_HAVE_OTEL