Merge pull request #10177 from kpayson64/no_gil

Change GIL aquire functions to make it c-core thread safe

src/python/grpcio/grpc/_cython/_cygrpc/security.pxd.pxi

@@ -29,4 +29,4 @@
 
 
 cdef grpc_ssl_roots_override_result ssl_roots_override_callback(
-    char **pem_root_certs) with gil
+    char **pem_root_certs) nogil

src/python/grpcio/grpc/_cython/_cygrpc/security.pyx.pxi

@@ -33,7 +33,8 @@ import pkg_resources
 
 
 cdef grpc_ssl_roots_override_result ssl_roots_override_callback(
-    char **pem_root_certs) with gil:
+    char **pem_root_certs) nogil:
+  with gil:
     temporary_pem_root_certs = pkg_resources.resource_string(
         __name__.rstrip('.cygrpc'), '_credentials/roots.pem')
     pem_root_certs[0] = <char *>gpr_malloc(len(temporary_pem_root_certs) + 1)
@@ -41,4 +42,5 @@ cdef grpc_ssl_roots_override_result ssl_roots_override_callback(
         pem_root_certs[0], <char *>temporary_pem_root_certs,
         len(temporary_pem_root_certs))
     pem_root_certs[0][len(temporary_pem_root_certs)] = '\0'
+
   return GRPC_SSL_ROOTS_OVERRIDE_OK