PS1: fix annotations

In 4e4e3f3, the 0; and bell etc. were incorrectly interpreted as having
to do with colors. In fact, it is responsible for setting the window
title. [1]

[1] http://www.faqs.org/docs/Linux-mini/Xterm-Title.html#ss3.1

Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>

etc/profile

@@ -153,9 +153,7 @@ esac
 
 . /git/contrib/completion/git-completion.bash
 
-PS1='\[\033]0;'                # VT100 compat: reset all colors
-PS1="$PS1"'$MSYSTEM:\w'        # e.g. MINGW32:/path/to/cwd
-PS1="$PS1"'\007'               # Ascii character BEL
+PS1='\[\033]0;$MSYSTEM:\w\007' # set window title
 PS1="$PS1"'\n'                 # new line
 PS1="$PS1"'\033[32m\]'         # change color
 PS1="$PS1"'\u@\h '             # user@host<space>