wendelin: Don't pin what is already included and pinned in erp5 SR

Both numpy and ipython are included in ERP5 SR which wendelin inherits
from, and are pinned there. Here are e.g. latest pin-ups for numpy and
ipython in erp5:

    e3144a8a    (version up eggs.)
    135570c9    (version up eggs.)

Furthermore: this is not only a cleanup. As e3144a8a shows current
version of numpy in erp5 is 1.10.4 and in wendelin we still have 1.9.2
which is unintentional downgrade compared to erp5.

Don't do that.

/cc @kazuhiko
/reviewed-by @Tyagov  (on nexedi/slapos!41)

software/wendelin/software.cfg

@@ -54,7 +54,5 @@ scikit-learn = 0.16.1
 scipy = 0.15.1
 pandas = 0.16.1
 msgpack-python = 0.4.6
-numpy = 1.9.2
 wendelin.core = 0.5
-ipython = 3.2.0
 matplotlib = 1.4.3