shruntime.py: fix wrong env var name
@@ -33,7 +33,7 @@ from .shthreads import ShBaseThread, ShTracedThread, ShCtypesThread, ShState, Sh
# Default .stashrc file
_DEFAULT_RC = r"""BIN_PATH=~/Documents/bin:{bin_ext}:$BIN_PATH
-SELFUPDATE_BRANCH=master
+SELFUPDATE_TARGET=master
PYTHONPATH=$STASH_ROOT/lib:$PYTHONPATH
alias env='printenv'
alias logout='echo "Use the close button in the upper right corner to exit StaSh."'
