rpm: do not install INSTALL file

this fixes the rpmlint issue:

    [  100s] naemon-core.aarch64: W: install-file-in-docs /usr/share/doc/packages/naemon-core/INSTALL
    [  100s] A file whose name suggests that it contains installation instructions is
    [  100s] included in the package. Such instructions are often not relevant for already
    [  100s] installed packages.

Author: sni

naemon-core.spec

@@ -299,7 +299,6 @@ exit 0
 %doc AUTHORS
 %doc COPYING
 %doc ChangeLog
-%doc INSTALL
 %doc LEGAL
 %doc NEWS
 %doc README