bash: add .profile

Some systems source .profile rather than .bashrc. Provide .profile as a
symlink to .bashrc.

Signed-off-by: Colin McCabe <cmccabe@alumni.cmu.edu>

diff --git a/.profile b/.profile
new file mode 120000 (symlink)
index 0000000..5157537
--- /dev/null
+++ b/.profile
@@ -0,0 +1 @@
+.bashrc
\ No newline at end of file