Fix OpenCV 3.4.1 issue for Scala package for OSX

[nswamy]

Currently OpenCV@2 package along with Scala package seems to be failing due to an existing opencv version.
modify scala-package/dev/compile-backend.sh to use OpenCV3.4.1

For Q & A and discussion, please start a discussion thread at https://discuss.mxnet.io

Description

(Brief description of the problem in no more than 2 sentences.)

Environment info (Required)

What to do:
1. Download the diagnosis script from https://github.com/apache/incubator-mxnet/master/tools/diagnose.py
2. Run the script using `python diagnose.py` and paste its output here.

Package used (Python/R/Scala/Julia):
(I'm using ...)

For Scala user, please provide:

1. Java version: (java -version)
2. Maven version: (mvn -version)
3. Scala runtime if applicable: (scala -version)

For R user, please provide R sessionInfo():

Build info (Required if built from source)

Compiler (gcc/clang/mingw/visual studio):

MXNet commit hash:
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Build config:
(Paste the content of config.mk, or the build command.)

Error Message:

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Minimum reproducible example

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Steps to reproduce

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What have you tried to solve it?

[kalyc]

@nswamy thanks for submitting the issue. The PR - https://github.com/apache/incubator-mxnet/pull/11147/files mentions that the OpenCV version will be updated in the next release

[nswamy]

Yes that is because we have already published the package and cannot undo without bumping up the version which will happen only after the next release.

[mariussoutier]

Will this fix the Library not loaded: /usr/local/opt/opencv@2/lib/libopencv_calib3d.2.4.dylib error?

[nswamy]

@mariussoutier. Yes it should fix that issue, however you could also install opencv2 on OSX as brew install opencv@2
We are fixing this in 1.2.1, the package is currently in staging
https://repository.apache.org/#nexus-search;quick~org.apache.mxnet. Feel free to test and provide feedback. see the instructions to use packages in the Staging repo here

[nswamy]

#11862 fixes the issue

[nswamy]

#11862