base: remove ssc-pimega source after installation.

Repository source contains several large binaries summing up to 119MB.
Remove it after build, since needed artifacts for next stages are only
headers and shared library, which are installed under /usr/local.

base/install_area_detector.sh

@@ -103,6 +103,7 @@ cd ..
 
 download_from_github cnpem ssc-pimega $LIBSSCPIMEGA_VERSION
 make -C ssc-pimega/c install
+rm -rf ssc-pimega
 
 install_from_github cnpem NDSSCPimega NDSSCPIMEGA $NDSSCPIMEGA_VERSION "
 EPICS_BASE