Fix android aar build

[ortex]

Built aar doesn't work

java.lang.UnsatisfiedLinkError: dlopen failed: library "libroc.so.0.1" not found
    at java.lang.Runtime.loadLibrary0(Runtime.java:1071)
    at java.lang.Runtime.loadLibrary0(Runtime.java:1007)
    at java.lang.System.loadLibrary(System.java:1667)
    at com.github.rocproject.roc.RocLibrary.loadLibrary(RocLibrary.java:5)
    at com.github.rocproject.roc.ChannelSet.<init>(ChannelSet.java:18)
    at com.github.rocproject.roc.ChannelSet.<clinit>(ChannelSet.java:14)

how to build:

export JAVA_VERSION=8 
export ANDROID_API=28 
export ANDROID_BUILD_TOOLS_VERSION=28.0.3 
export ANDROID_NDK_VERSION=21.1.6352462 
export ROC_BASE_DIR=$HOME/roc-build

./scripts/travis/android/install.sh 
./scripts/travis/android/script.sh 

how to reproduce:

• clone https://github.com/roc-project/roc-droid
• replace https://github.com/roc-project/roc-droid/blob/master/app/libs/roc-android-release.aar with android/roc-android/build/outputs/aar/roc-android-release.aar
• try run app and click start

As a temporary workaround to build arr I changed in https://github.com/roc-project/roc/blob/master/SConstruct#L1079
from

lib_env['SHLIBSUFFIX'] = '%s.%s' % (lib_env['SHLIBSUFFIX'], abi_version)

to

lib_env['SHLIBSUFFIX'] = '%s' % (lib_env['SHLIBSUFFIX'], abi_version)

[gavv]

Note: ironically, soname and symlink feature was first introduced specifically for Android port: roc-streaming/roc-toolkit#222 (comment)

[MatteoArella]

Yes gradle plugin doesn't pack shared libraries with extensions that differ from .so so libroc.so.0.1 file won't be packed inside aar.
I've fixed setting LDFLAGS="-Wl,-soname,libroc.so" before building roc library with scons