Fix boringssl template as well

templates/src/objective-c/BoringSSL-GRPC.podspec.template

@@ -1552,7 +1552,7 @@
       EOF
 
       sed -i'.back' '/^#define \\([A-Za-z0-9_]*\\) \\1/d' include/openssl/ssl.h
-      sed -i'.back' 'N;/^#define \\([A-Za-z0-9_]*\\) *\\\\\\n *\\1/d' include/openssl/ssl.h
+      sed -i'.back' '$!N;/^#define \\([A-Za-z0-9_]*\\) *\\\\\\n *\\1/d' include/openssl/ssl.h
       sed -i'.back' 's/#ifndef md5_block_data_order/#ifndef GRPC_SHADOW_md5_block_data_order/g' crypto/fipsmodule/md5/md5.c
       find . -type f \\( -path '*.h' -or -path '*.cc' -or -path '*.c' \\) -print0 | xargs -0 -L1 sed -E -i'.grpc_back' 's;#include <openssl/;#include <openssl_grpc/;g'
     END_OF_COMMAND