dont print python stacktrace when build fails

Fixes #2068 (closed)

To test:

1. Edit ~/.local/var/pmbootstrap/cache_git/pmaports/main/hello-world/main.c:

diff --git a/main/hello-world/main.c b/main/hello-world/main.c
index 8ac5cc3ee..826a4ec32 100644
--- a/main/hello-world/main.c
+++ b/main/hello-world/main.c
@@ -2,6 +2,6 @@

  int main()
   {
   -       printf("hello, world!\n");
   +       print("hello, world!\n");
           return 0;
   }

This should generate a compile time error

2. Run ./pmbootstrap.py checksum hello-world && ./pmboostrap.py build --force hello-world

Run ./pmbootstrap.py log does not have the python stacktrace for the hello-world failing to build