Yamashita, Yuu d8559b9749 Workaround for performance issue with conda.txt ...

The performance issue must be caused by too many I/O requests to
`conda.txt` from fgrep. This inline expansion should work to reduce # of
read to the `conda.txt`.

original performance:

```
% git rev-parse HEAD
4f76be6a12
% time bash -c 'pyenv rehash'
bash -c 'pyenv rehash'  0.05s user 0.02s system 76% cpu 0.089 total
```

previous commit: ==> 4x slower than original

```
% git rev-parse HEAD
4469d51ef7
% time bash -c 'pyenv rehash'
bash -c 'pyenv rehash'  0.06s user 0.03s system 25% cpu 0.358 total
```

with this workaround: ==> almost same as original

```
% git rev-parse HEAD
3ffe91bdbc69220eaecf6e2088229cc27366c3f3
% time bash -c 'pyenv rehash'
bash -c 'pyenv rehash'  0.05s user 0.00s system 68% cpu 0.082 total
```

2016-08-15 05:49:50 +00:00

..

exec

Run rehash after conda install

2015-12-23 08:09:40 +00:00

rehash

Workaround for performance issue with conda.txt

2016-08-15 05:49:50 +00:00